How long does your engine have to run for the temperature gauge to start reading? I have VDO gauges and VDO sending units. Everything else works so I'm assuming I have it wired correctly. I took the car for a spin around the block (less than a mile). And the temp gauge didn't move. I just want to make sure it's working before I take it on a longer drive. Is there any way to test it?
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Less than a mile? Yeah, probably didn't heat up much. Drive it around for 30 minutes or so.
I also have VDO gauges. It takes a while, even if it's warm outside. Longer when it's cool. The oil has to rise above 120°F for the needle to move. Mine takes 10-15 minutes at least to get to 180°F.
Awesome. Good to know. Thanks guys I just didn't want to keep running it without everything working properly. Especially the engine temp.
In the winter (yes, I drive down into the 20F range) the needle might get up to 1/4" above "cold" after 30 minutes or so, longer if I'm just on back roads. I have an external oil cooler bypass when cold, but 1/4" on the needle is about all regular old VW Beetles did in winter. Most of the time, the needle barely got up off the bottom stop in winter.
In the summer, it gets up around 1/3'rd of the range if it's really hot out, but that takes 15-20 minutes or so of driving to get it there.
Since there are no numbers on the gauge at what point would be cause for concern? I'm assuming more than halfway like on most other vehicles however on this gauge the red is just a little section all the way to the right
Since there is so much variability between what the gauge expects to see for sender resistance and what the range of each available sender might be, it is really hard to tell, especially with gauges that are just a bar graph with no numbers.
The only way to really tell is to buy a candy thermometer roughly as long as your dipstick and with a range between 175F and 250F. Doesn't matter if it is digital or analog. They usually come with a pot clip which you can use to set the depth of the thermometer probe to the same length as your original dipstick.
Then, go for a ride to get it warmed up, like at least 30 minutes. Stop, shut it down, pull your dipstick and insert the candy thermometer and wait a minute for it to stabilize and see what it says. You can do this after running on back roads, and after a long stretch on a freeway which will drive your oil temp up about as high as it will go. Once you really know what the engine oil temp is, you can correlate that with where your gauge needle is and have a better idea of overall engine temp under different running conditions. You can even put a mark on the gauge face so you'll know what the top of your range is.
And what is that range? you might ask... Well, for moderate summer ambient temps, like 75 - 90F, the following would be close:
Normal around town: 180-200F
Moderate secondary roads 200-205F
Freeway 200-210F
Getting too hot, so pull over 215-220F
Your mileage may vary, depending on a lot of things.
Another point to consider, is where the temp sensor is located.
When I had a gauge that did not have numbers, I did what Gordon suggested with the thermometer and a grease pencil. Then I replaced that gauge with one with actual numbers and found that my temps were running low, but my thermometer was showing higher. Well, my temp sensor in located in my aftermarket sump. I found that the temp there, is cooler than when I stick the thermometer down my dipstick hole.
I will be relocating that sensor at some point, but now I know.
I agree with Gordon's numbers, but my "pull over now" limit is about 240 F. Modern oils, especially synthetics, are fine up there. Some guys run their Formula Vees up there on hot days, but mine never goes up there. So far, that is.
My truck runs almost 240 F when towing up long grades in the summer, but only when I let the trans downshift and maintain 4000 revs or more.
My Spyder never runs over 200 F, so I don't have to worry about it at all.
I’ll see your dumb question and raise you another: Do you have the OEM thermostats and flappers? They were designed to deflect cool air away from the cylinders until the thermostat opens and if you don’t have them your engine will take longer to warm up.
Even with the flappers I would drive 2-3 miles before the needle even passed the bold line to the left. Once warmed up my gauge would stay right between the two bold lines at 12:00 high unless I was climbing a grade. The road up to Sundance ski resort is about 4-5% grade and the needle would be about 3/4 to the right line when I pulled into the parking lot after 6 miles in 3rd gear.
I have questions. Are they dumb? Probably. I hear that there are only dumb answers, so lets see how this goes.
Even going back 50 years to my early 356s, I always thought the temp gage should run at about straight up. Say half way. On My usual Sunday drives these days and short hoons around town, usually in fair weather, and it hardly gets there. Then . . . I ran up to southern PA a week or so ago and the ambient was 90+, a pretty hot, very sunny day. So 90 minutes or so at highway speeds. My needle just kept climbing. at one point it just touched the red bar on the right. i was only a few miles from home then and so just ran it to the garage, where it cooled down to far left in about 30 mins being turned off. It smelled hot, but not unusually so. When I turned the ignition on after the cool down, I noted that the fuel pump ran on a bit filling the float chambers. The car has never run much past 3/4 on the gage before. SO, QUESTIONS . . . I Have not done the candy thermometer thing yet, but will. So more definitive data is coming, what temp would be at the red bar on right? Should I get an oil cooler? I have an OEM cooler in the shroud, so far as I know. Do these things have thermostats? Do they fail? How about sending units? I think I have OEM VW, will have to check. Do they fail? Is there a resistance vs temperature chart for these things? And i hear that there may be two different kinds with different calibrations. Pls help to sort this out.
Furthermore . . . Im pretty sure I have a dual sender: temp and pressure. I all my searches on line now, I cannot find any such thing, making me think I have imagined a thing that does not exist. When I get to my car I'm going to look very carefully. I do see temp senders that fit in to the Type 1 oil pressure relief plug. Hmmm . . . wonder if I could do that? This has gotten complicated.
Would this help? It's a stock Brazilian VDO gauge (or Chinese copy thereof) from 2005, with the temperature gauge rescreened by Harmut to display actual temperatures. I wasn't a fan of "no numbers" either. Pay no attention to the idiot light icons and the oil pressure gauge instead of the useless fuel gauge, the temperature gauge is the the same guts, with the same sender -- only the face of the gauge has changed, so the numbers would be close for you as well.
Is it accurate? It's close enough to let me know when something is not right. In my world, cruising at 180 is ideal. 180 to 240 is 60 deg, so the mark between them (Kelly's "nearly straight up") is 210-ish, which is fine (pretty ideal, in fact). My limit is 240 deg. It's not the oil breaking down that's the issue -- it's dropping a valve seat that you want to avoid. At more than 240 deg, the aluminum in your heads isn't gripping the valve seats (made of a metal with a much higher melting point) very hard anymore, because the aluminum of the head is growing much faster than the valve seat material. If you don't drop one, you're still hammering them into the head at those temperatures.
Extrapolation: anything from 11:00 to 1:00 is probably OK. If you get over into the band on the right, it's not so great.
@El Frazoo posted:I have questions. Are they dumb? Probably. I hear that there are only dumb answers, so lets see how this goes.
Even going back 50 years to my early 356s, I always thought the temp gage should run at about straight up. Say half way. On My usual Sunday drives these days and short hoons around town, usually in fair weather, and it hardly gets there. Then . . . I ran up to southern PA a week or so ago and the ambient was 90+, a pretty hot, very sunny day. So 90 minutes or so at highway speeds. My needle just kept climbing. at one point it just touched the red bar on the right. i was only a few miles from home then and so just ran it to the garage, where it cooled down to far left in about 30 mins being turned off. It smelled hot, but not unusually so. When I turned the ignition on after the cool down, I noted that the fuel pump ran on a bit filling the float chambers. The car has never run much past 3/4 on the gage before. SO, QUESTIONS . . . I Have not done the candy thermometer thing yet, but will. So more definitive data is coming, what temp would be at the red bar on right? Should I get an oil cooler? I have an OEM cooler in the shroud, so far as I know. Do these things have thermostats? Do they fail? How about sending units? I think I have OEM VW, will have to check. Do they fail? Is there a resistance vs temperature chart for these things? And i hear that there may be two different kinds with different calibrations. Pls help to sort this out.
I'm certainly not an expert but here's my .02.
1) what temp would be at the red bar on the right? I'd like to know the answer myself
2) Should I get an oil cooler? I would ask what size engine do you have? 1600 -1641 cc, you probably dont need one, but it wouldn't hurt. The stock oil cooler if functionimg correctly is more than adequate. Anything over that I'd say yes. Again, Im no expert and until you're at the 1900+ cc range it probably isnt absolutely necessary but I still would. Engines are expensive so why not spend $300 for a proper oil cooler kit and protect your investment.
3) Do these things have thermostats? Sending units? Do they fail? Yes they have thermostats but can be ran without them. The thermostats open the vanes on the fan. So if you live in colder climates the thermostat keeps the vanes closed so your engine warms up faster. Sending units? Not stock (at least not in the early models. Later models I have no idea if they had temp gauges or not. If they did, then yes, there would have to be a sending unit if theres a gauge. The ones you see that go into the relief plug is what I have. That's where my vdo sending unit is. People also tap the case and put them in there (I believe around where the oil pump goes.) Do they fail? I won't say no but I've never heard of one failing so it must be petty rare.
4) Resistance vs temperature chart? That would answer question 1 if we knew. Or would at least give us the ability to answer question 1. I've also heard that the temp and fuel Sending units and gauges are the same. The gauges may be and have the same resistance so if someone wanted to do some experimenting it could probably be figured out. The Sending units are definitely not the same though
Kelly, since you've never seen it that high before, could it be possible that something has changed? Maybe you're low on oil or something.
@El Frazoo your "dual sender", if you have one, is for oil pressure and the red dash idiot light. That is the only dual oil sender I know of. It will have two plastic thumb screws on it.
I've never heard of a dual sender for both pressure and temperature. I'm not saying it doesn't exist, but I've never seen one.
MANY (too many, mine included) don't have a thermostat and flaps under the shroud, but should.
Kelly, you have a 2332cc, which IMHO should definitely have an external cooler in addition to the one under the shroud. Anything over an 1835cc should have one.
Stan, I know you know this, but your heads run a lot higher than 210 F. Heads run anywhere from 270 F to 350 F. Above that and you'll probably hammer some seats. I do agree that there is some correlation between oil temp and head temp.
I know you have CHT sensors. What do they usually run?
I do agree that gauges with no numbers are stupid. Having said that, my old oil temp gauge would read about a third of the way. It would get to straight up on really hot days. My current car with Speedhut gauges reads 180 to 195.
@DannyP posted:My current car with Speedhut gauges reads 180 to 195.
Where, on your engine, is your Speedhut temp sensor screwed into?
Carlos, it's at the OE oil pressure switch location, with a special T for it and the 10mm x 1 pressure switch.
Update, and thanks all for the engagement.
What I have is a T fitting in the block near the dizzy that holds the idiot light pressure switch and a temperature sensor. I also looked up the OEM oil cooler system in my VW manual and it shows a thermostat clap-trap mounted typically under the engine in some proximity to push rod tubes. ?? Anyway, I have no such clap-trap. I think I recall from JPS , and Danny has seconded, that most of our non-OEM Type 1s do not include this thermostat. Kind of explains why the oil temp does not rise up very fast. Which is not a problem.
Further data: 2332 cc, 44 IDFs, 110 cam, and some other stuff that comes along with the larger engine; Magnaspark complete dizzy and coil system. On the particular trip explained above, the oil (10W-30 Brad-Penn) was freshly changed. Only at the very end of the trip did the pressure light flicker at idle, which is about 1,000 rpm. The engine used no oil to speak of during that adventure, and put two drops of oil on garage floor while it was cooling down; usually it drips pretty much not at all.
External Oil cooler: I'm not averse to having one, although I have been now 20k+ miles and over ten years without issue. It would be nice to be able to drive in truly hot conditions and not have to worry about overheating. So the question: what changed? All I can offer is the weather. Heretofore, my longest trips have been back and forth to Carlisle (usually in very mild if not downright chilly air, often including precipitation and maybe 90 minutes), and various half day and full day cruises in PA, NC, VA, where the car is driven, often hard, pretty much all day, but with frequent stops and all with mild air temps. For Tour d'Smo adventures, the car is flat towed to the event. Someone offered that maybe I'm running lean?? Well, that would be a first, as my car has never been accused of that. Tail pipe is a dark charcoal grey. It has been downright sooty on some occasions, but that seems to be in the past, after some recent careful tuning and TLC to the Webers. I think my gas mileage is in the low to mid 20s.
I hear external oil coolers go in the rear wheel well, and this seems dangerous. Provides good opportunity to gather dirt and other unwanted there. There is a crazy amount of room between "firewall" and back seat, but maybe this is not a well ventilated area? Also I have heard that one can cut a hole in this fiberglass septum adjacent to the fan opening and help out with air flow through the fan. I can certainly do that, but only if the air pressure back there is positive wrt the engine compartment and particularly the fan inlet. seems I heard some data were taken about air pressures once upon a while back, and curious results were obtained. If the pressure in this space goes down with car speed (as it might) , cutting a hole in the wall would be counterproductive. I've also heard that you can prop open your engine lid to help with air flow, but others have tried this and seen little if any beneficial effect. Or so I am told.
Has anybody replaced their oil pressure relief plug with a temperature sensor? I see these offered.
@El Frazoo Are you overthinking this? In a word, yes, but not too much.
Remember, it's just a big lawnmower engine.
"I have an OEM cooler in the shroud, so far as I know. Do these things have thermostats?
Not really. The only thermostat is below the cylinders on one side and controls the air vanes inside the fan shroud. I would like to think you have air vanes but if there's no bellows thermostat then probably no air vanes, too. To check, there should be two shafts protruding from the front or back of the shroud, at the bottom and just above the heads. No actuator shafts and no bellws thermostat = no air vanes. There have been arguments on the Samba on whether it's better or worse to run without air vanes, even on hot days after warm up. I have them on my 2,110 and it runs cool.
Do they (thermostats) fail?
Sure - from time to time.
How about sending units? I think I have OEM VW, will have to check.
We don't know what el cheapo sender Steele put in there. Anything would be a guess.
Do the senders fail?
Absolutely, and more often in these days of poor quality imports.
Is there a resistance vs temperature chart for these things?
Yes, but it varies from sender to sender and even then might not be totally accurate.
And i hear that there may be two different kinds with different calibrations.
Possibly - I don't know. I have separate senders for oil temp and oil pressure in the same location as you. I think I had one dual sender once, but I'm pretty sure they are now separate.
What I would suggest, before you get too far wrapped around the axle, is find out what the heck is really going on back there:
Go get the candy thermometer to find out what temps your engine is really running at. Without that, you're only guessing and spinning your wheels. Once you know what's what, temp-wise, THEN you will have a better idea of the direction to take. And remember - It's a LOT easier to install or replace a sender behind the distributor than one taking the place of the oil pressure relief valve plug.
Once you know what temps you really have AND how they correlate to the numbers on your gauge (You have numbers? You lucky dog...) you could calculate the value of a resistor (or just use a suitable potentiometer) to wire in parallel with your sender to fine-tune the gauge needle to be more precise, or you could just note how far off the needle is to reality at critical temps, like 200º-ish and 220º-ish. (That seems like an easier approach, to me).
As you know, I have an external cooler in the left rear wheel well. Everything I did to install it is up in the "Knowledge" section, but you don't yet know if that would help you. Find out where you are, first! That will tell you what to do.
I also have a later (1971 - 1979), larger, OEM VW "Dog House" fan shroud with all of the air vanes, bigger fan and thermostat installed. When I was building my car I was reading about cooling prblems with 2,110 and larger engines and did everything mentioned in "Hot VWs" magazine to keep it cool except for the external cooler. That was added after four years and it helped a whole lot, like freeway temps went from 220º down to 205º.
Txs ever so, Gordon. I have been off line the last few days with cataract surgery, which seems to have gone very well, I can actually read and type shyt here on the SOC without my readers. Only two days since , so very much adjusting. Candy thermometer next, and my gage does not have numbers, I'll look to see if sender has any identifying engravings, although my new Magnaspark dizzy is going to make having a easy look-see a little tricky. I will measure some resistances, I suppose it could be "calibrated" in a pot of boiling water.
Still looking for an idea about cutting that hole in the firewall opposite the fan inlet. I've heard conflicting reports. And I am not adverse to making some pressure measurements of my own while driving at various speeds to see what is really going on back there. 3,000 rpm 4th gear would be a fine data point. That space where the tranny is, ... plenty of room between the firewall and the jump seat bulkhead. But if there is a nice slip stream running under the floor pan past that space, the pressure there could go down relative to the engine compartment, and that would be contraindicated. Like Unit Five: need more data . . .
I have a light wired to my fan/thermostat to let me know when it turns on. It's supposed to kick on at 180. Im to going to check and see where the needle is on the gauge when that happens. That'll be my starting point at least. I'll report back with the results
Bump:
I got my candy thermometer, and had a chance to do a mild hoon yesterday, and run up the temperature. With my unmarked temp gage needle at about vertical, which I have always assumed is more or less a good operating temperature, I measured 221 F at the dipstick. So, how about that?
Anybody??
221F seems just a little warm for me, although not worrisome. After you hoon and turn off the engine it will gain a few degrees. Mine had a thermostatically controlled external oil cooler and usually ran right around 210F during normal driving and 225F going 20 miles up the volcano.
My normal gauge position was around 3/4. I suspect you are doing just fine.
I'm still leaning hard toward adding the external oil cooler/fan thing. Seems like just about everybody does it. Just so much extra plumbing, seems like. The real deal here, as explained initially here is the wild excursion all the way over to the right during a long highway run in 95 deg heat this summer. That caused me some concern, as reported. Better if it could handle really hot days without getting too hot, what with climate change, and all . . .
When I put my external oil cooler on, I went ahead and removed the internal cooler so all of the heat would be dissipated in the wheel well instead of inside the engine tin. Bought a block off plate and never looked back. I did spring for the thermostat so the engine would warm up more quickly and a thermostat switch for the fan. I never had a problem with it
If you have a doghouse shroud the stock oil cooler heat gets dumped outside the engine tin.
I have both the stock cooler and an external cooler with a fan.
The fan has a switch that turns it on at 180 degrees. Some put this switch on the inlet side of the cooler. I put it on the outlet side. My thinking was that I don't care if the oil enters the cooler hotter than 180. I only care if it exits the cooler hotter than that. If it does, the fan comes on. A light in the combo gauge tells me if the fan comes on. Much of the time the fan isn't needed.
Most of the time my oil temp stays around 180.
If you do choose to keep the stock cooler, invest in a tiny piece of engine tin called the Hoover Bit. It helps to seal air gaps around the cooler and the engine tin so it works more effectively.
You may already have the Hoover Bit. I would check first before ordering one.
It is good advice from @Michael Pickett to be sure you have one.
You should also have foam over the top of the cooler to seal against the tin.
If you don't have the Hoover Bit, my guess is that adding one will obviate your need for a full external cooler setup. The other thing: make sure your spark plug wire flappy bits are arranged just so—with no air leaks around them. Your sled tins are in place, right?
220 seems a little high to me as a normal operating temp. I'd want to see it about 210 to leave a little headroom for those 95-degree Carlisle traffic jams.
The Spyder ran 180-190 with the extra oil cooler, and was close to your number without it.
Here's the thing: I think that displacement is directly related to engine temps WITHOUT an external cooler. Mike Pickett had a 1776cc. Ed had a 1915cc.
My Spyder is a 2165cc, but with a huge oil thermostat-equipped and thermostatically fan-cooled 96 plate cooler. It runs 190 MAX. Period.
Kelly has a 2332. More displacement, more heat.
IMHO EVERY engine over 1776cc needs an external cooler. Especially if it is hot-rodded in any fashion above stock.
My little 1200cc FV runs 190-200, but has been as high as 230F on a hot day during a LONG race. No fans, just ram-air cooling. The cooler I have is a Setrab that is a bit larger than a stock oil cooler. FWIW, the engine is hot-rodded: factory was 40 hp and we're getting 60hp now.
So even a small motor can run on the warm side. That is why we change the oil every couple race weekends. Modern oils will survive higher temps than when VWs were popular.
But for Kelly's situation, I'd DEFINITELY add an external cooler in the wheel well. He would drop temps by 20 degrees at least.
The airflow through a Speedster engine bay is notoriously terrible -- way worse than a VW beetle or Ghia, and about as bad as a bus.
I don't (and never have) understood the reluctance to just putting a remote oil cooler on the car. It can't hurt. It can only help. Do the whole thing, with a pressure relief filter base, a Mocal sandwich bypass, and a fan thermostat. Guys who say you don't need them either have a puny 1641, live in Saskatoon, or both. Nobody can know of a certainty where they'll end up driving their car. Do you REALLY want to stop out on a highway in Barstow so your car can cool off?
Buy once, cry once -- forever run cool oil.
@El Frazoo posted:I got my candy thermometer, and had a chance to do a mild hoon yesterday, and run up the temperature. With my unmarked temp gage needle at about vertical, which I have always assumed is more or less a good operating temperature, I measured 221 F at the dipstick. So, how about that?
Q: How about that?
A: Um...
A full month ago, on 7/22/24 @Stan Galat posted:
Would this help? It's a stock Brazilian VDO gauge (or Chinese copy thereof) from 2005, with the temperature gauge rescreened by Harmut to display actual temperatures. I wasn't a fan of "no numbers" either. Pay no attention to the idiot light icons and the oil pressure gauge instead of the useless fuel gauge, the temperature gauge is the the same guts, with the same sender -- only the face of the gauge has changed, so the numbers would be close for you as well.
Is it accurate? It's close enough to let me know when something is not right. In my world, cruising at 180 is ideal. 180 to 240 is 60 deg, so the mark between them (Kelly's "nearly straight up") is 210-ish, which is fine (pretty ideal, in fact). My limit is 240 deg. It's not the oil breaking down that's the issue -- it's dropping a valve seat that you want to avoid. At more than 240 deg, the aluminum in your heads isn't gripping the valve seats (made of a metal with a much higher melting point) very hard anymore, because the aluminum of the head is growing much faster than the valve seat material. If you don't drop one, you're still hammering them into the head at those temperatures.
Extrapolation: anything from 11:00 to 1:00 is probably OK. If you get over into the band on the right, it's not so great.
But, of course, the only true oil temperature reading you can get on ANY car to prove the accuracy of the dash gauge is to use a dipstick thermometer, calibrated in a cup of boiling water at 212ºF so you know the accuracy, and then run the car and test the oil temp. Anything else is just speculation.
@El Frazoo posted:Like Unit Five: need more data . . .
@Gordon Nichols posted:But, of course, the only true oil temperature reading you can get on ANY car to prove the accuracy of the dash gauge is to use a dipstick thermometer, calibrated in a cup of boiling water at 212ºF so you know the accuracy, and then run the car and test the oil temp. Anything else is just speculation.
This is true, and I've done it with my CHT gauges.
However, it's important to remember that there are 2 kinds of people in this world:
@Gordon Nichols posted:But, of course, the only true oil temperature reading you can get on ANY car to prove the accuracy of the dash gauge is to use a dipstick thermometer, calibrated in a cup of boiling water at 212ºF so you know the accuracy, and then run the car and test the oil temp. Anything else is just speculation.
This. Do it and remember how the temps correlate to your gauge and regardless of your sensor or gauge calibration, you'll know how happy your engine is at a glance.
I'm reminded of the old GMC "Astro 95" tractor-trailer tractors of the '60's and 70's which had a dash panel off to the driver's right which held something like 10 small gauges reporting on all sorts of important stuff, arranged by driver importance. The panel was designed by engineers with a LOT of input from all sorts of truck drivers, so when everything was operating normally, all of the gauge needles pointed straight up (the gauges all had real numbers on their scales, too). That meant that the driver knew if he had a problem with just a glance. I drove one of these sometimes when I was in college. They were a pretty advanced design that got copied by everyone else.
I love information. More is more. That bus dash is the bomb.
@Stan Galat posted:This is true, and I've done it with my CHT gauges.
However, it's important to remember that there are 2 kinds of people in this world:
- Those who can extrapolate from incomplete data
2. Those who like pie.
