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Discussion starter · #202 · (Edited)
Well ECU swap didn't change a thing.

So What I did manage to observe doesn't bode well.

Drove for a while, it starts going up after 20-30 miles as usual.
I go home, watch it carefully while IR reading various places. The input (pass) side of radiator side tank is 165-170f while the gauge/engine out reads 230-240f. I can IR gun the output sensor directly it is about 230-240f. Output side of radiator side tank is 75-80F. If you let it go until the temp reaches 250 or so, the rad fans go to 95% duty cycle full on, input side of rad is 165 output is 65.The output side is commensurate with VCDS reading. So is the iengine out temp at least at the sensor itself on the back of the block when I get my IR gun on it. So sensors I think are OK. I think the radiator is fine, but somehow.. hot engine .water is not reaching the radiator. So....how could that be?
I was half ready to throw a radiator at it but it seems the radiator is capable of a large delta and that hot water is just not reaching the radiator.
 
Does it get that hot at home or only when you are driving?

Do you let it warm up at home? Have you tried idling it at home until it heats up?

Mine get hot enough during scans for the engine fans to come on.

Maybe a hose has a blockage or a previous owner connected the hoses wrong.

You can point the IR thermometer at both ends of the hoses to see if a hose has different temperatures on each end.

Have you tried revving the engine at home to the same RPMs as when you are driving?

Maybe the engine twists at higher RPMs and collapses a hose or something else happens at higher RPMs.

Maybe a hose collapses on its own at higher RPMs or after it warms up.

Is there something that blocks the radiator when you are driving?
 
Discussion starter · #204 · (Edited)
SO here's a drive from yesterday on my car over about 30miles.


Here's Stephan's Drive from yesterday same data:


ANd here was my original problem before I did anything drive




My Original problem seems to have a t-stat that works initially but stops working
Clearly the change og t-stat and sensors did something on my car. But now it seems the t-stat is not working at all.
Stephans car clear shows t-stat cycle and rad output temp goes up, and there's a clear cycle there.


From last nights observations where I can IR gun the input side of the radiator and it's basically not getting hot water. During the afterun it does and I get a big delta. If I restart the car right away and tthe fans come on full, I get the same delta Stephans is, so I don't think a radiator is gonna help.
So either I have some blockage somewhere in the system, or perhaps I got a bum t-stat? Blockage seems a little unlikely as in my original problem shows at least initially t-stat opens and I get a increase in rad out temp. Now it appears I get nothing or next to nothing to the radiator. Which is commensurate with turn on heater and and I can somewhat control it if ambient is low enough. How likely is a bum t-stat out of the box. I know on SBC aftermarket ones, it's quite likely, but new from VW??? I dunno. I suppose it's also possible a mouse crawled up into the block somewhere when it was open for draining. I did leave it overnight the hoses open disconnected. It was on a lift though, but mice are known to perform acrobatic moves snd they like sweet coolant, but this G13 stuff is organic based it's not sweet like green prestone.

After reviewing historical weather data, I don't think this problem existed prior to me buying the car and it working fine in the cold months when I first got it. I know I drove it down to my cutsomer 200mi away on June 8th and weather says it was 68-82 that day or around 77 while I was driving, so no way it would have made it 200mi in that ambient temp and it was not having an issue on the way down there, no problems at all, until my return trip on the 12th when the temp was around the same in the mid to low 70's.

I dunno, perhaps it's wishful thinking ... but the ability to have the behavior change with t-stat and sensors followed by no water flow where there was some...i'm kinda thinking I got a bum t-stat?
 
Discussion starter · #205 · (Edited)
According to the schematic of the cooling system, the rear sender (5) is right in the main output pipe which runs through pipe (29) goes to a tee which feeds both radiators. And both radiators return to the tstat housing.



I mean, in the grand mess of stuff in that cooling system, the main loop is fairly contained and simple. So there's either blockage in that pipe from the rear of the motor to the radiators or the tstat isn't opening or the main water pump isn't moving. I don't think there's blockage in the motor itself, because if the afterun pump runs which bypasses the t-stat (it goes to the t-stat housing but to that other inlet which routes right to the back not through the main t-stat in there), the motor temp drops. If you turn the heater on, which bypasses the tstat, the motor temp drops. So the motor is capable of being cooled. I think main water pump is safe to declare ok. The main radiator isn't getting hot water so it's not the radiator, besides there's two. It kinda has to be that t-stat not letting water pass.
 
I would agree with your assessment that the t-stat is most likely not working/staying closed. As you can see from my drive cycle the radiator isn't really used that much with the current ambient temps so that would explain why it takes a while for your temps to get excessive and the fact that the heater cores and after-run can sufficiently cool it is another indicator. A blockage is a possibility but for something large enough to get in there it really would have to be something like a mouse crawling in there while it was open.

I'm assuming that the t-stat duty cycle data is the commanded value not the actual feedback from the t-stat. Did you do the electrical check at the connector as listed in the original t-stat replacement thread by Michael Moore? I remember there was a test to be carried out to ensure the VW warranty paid for a new t-stat.
 
Discussion starter · #207 · (Edited)
I did not do that test.
However, it is supposed to mechanically open at 210 or 215 or something as a safety backup and it goes way beyond that. So....i dunno.

Here's the 64,000$ question, if a mouse crawled up into that main pipe from the back of the engine to the radiators, wouldn't it boil away eventually at least the main body. I mean people boil deer and caribou and moose skulls to get all the organic material off the bones, and if your not careful you can boil away the bones if you leave it too long. My point is, I would surmise that condition would slightly get better after a few hot drives, or enough water would pass eventually to not cause a problem at these ambient temperatures.
 
Discussion starter · #208 ·
Does it get that hot at home or only when you are driving? - BOTH

Do you let it warm up at home? Have you tried idling it at home until it heats up? - Yes, it will overheat

Mine get hot enough during scans for the engine fans to come on. - the fans go to full when it hits 240ish but doesn't help anything input side is still same temp

Maybe a hose has a blockage or a previous owner connected the hoses wrong. - possibly

You can point the IR thermometer at both ends of the hoses to see if a hose has different temperatures on each end. - I might try that but if no water is moving thru one end will be hot the other cold

Have you tried revving the engine at home to the same RPMs as when you are driving? -yes, doesn't help anything

Maybe the engine twists at higher RPMs and collapses a hose or something else happens at higher RPMs. - that engine doesn't seem to move at all in there

Maybe a hose collapses on its own at higher RPMs or after it warms up.

Is there something that blocks the radiator when you are driving?
Answers in bold
 
You can point the IR thermometer at both ends of the hoses to see if a hose has different temperatures on each end. - I might try that but if no water is moving thru one end will be hot the other cold

Answers in bold
Exactly. One end will be hot and the other end will be cold if there is no flow. If a hose is cool when it's supposed to be hot, that's probably also an indication of no flow.

I'd suspect air in the system but It's possible the thermostat is bad. Can you point the IR Thermometer down on the Thermostat output hose?
 
Not sure what to suggest next, I guess verifying the t-stat responds to commands and the main tubing/hose going to the radiator has flow. The clear tubing is a nice trick but probably difficult to do on the radiator end with the proprietary fitting which makes it impossible to connect to.

Btw, did that Dayco serpentine belt work out ok, is it a good fit? Might snap up a couple at RockAuto for that low price.
 
Not sure what to suggest next, I guess verifying the t-stat responds to commands and the main tubing/hose going to the radiator has flow. The clear tubing is a nice trick but probably difficult to do on the radiator end with the proprietary fitting which makes it impossible to connect to.

Btw, did that Dayco serpentine belt work out ok, is it a good fit? Might snap up a couple at RockAuto for that low price.
Not to mention that the W12 has a zillion hoses. Which expensive hose do you cut up to see if it has coolant flow?

I'm also curious about the Dayco belt.
 
Discussion starter · #213 ·
The Dayco belt seems to fit perfectly. I compared it's effective length to the OEM, same (I don't remember the number now some mm I think worked out to 101.4").
It was slightly shorter than the one I took off but that's attributed to those things will stretch some for sure. The tensioner needed moved all the way to get the belt on and only came back slightly so the tensioner has pretty much full range to move back still. And, it's quieter than the old one, which I've no idea what brand it is as being dual sided ribbed there's no name or numbers on it. The dayco belt seems to be some poly fibre/rubber mixture, they actually tout it will be quieter and more durable than most oem belts. WHo knows, but it fits, it is quieter (by quieter I mean, you can't really hear the old one with the hood closed but I've spent soo much time with the engine running and hood up I noticed it was quieter.
 
Discussion starter · #214 · (Edited)
I was able to get to the t-stat connector on the back of the block, disconnect it and there was just enough to get the t-stat lead up above where I can jump it. I'm gonna try warming it up and forcibly just 100% open by putting 12v to that t-stat lead.
I did measure it's resistance, it's 15-16ohms right where it's supposed to be.

And..... it warms right up and keeps going. I plugged the t-stat to 12v constant and left it and it warmed up in the same amount of time it normally does, and keeps going up. I was able to get the IR gun on the main pipe under the right cylinder bank it's consistently hot, 230-240ish at the back of the block, 220-230ish at the front tee, and rad input tank on the right side is 190-200ish.
With a wide open t-stat it shouldn't warm up at least not quickly, I mean that thermo-resistor in there isn't gonna open when the block is cold not sitting in cold water aka it's not gonna heat all that water enough to warm it enough to open..., but it certainly shouldn't warm up nearly as quickly. And once at temp it should basically just be wide open.
I did get the code tthat says open map controlled t-stat circuit, so, the computer saw I had it disconnected which was expected.

I was also able to verify the plug coming from the computer that operates the t-stat had a voltage commensurate with the duty cycle, aka 10.5v for 80%, 8v for 60%...etc. I don't remember the numbers exactly but it went up and down with the duty cycle displayed in VCDS. 85% which is the max the computer will go was like 11.2v or something IIRC.

I dunno, it seems the t-stat is....not opening to me.
 
I think at this point you need to verify flow through the radiator alone. If everything seems good on the control end, a block radiator or poor flow through it effectively could look like a blocked thermostat. The reverse is true. The testing you've done can suggest a blocked radiator as forcing the t stat open on warm up yields no change in warmup times because there's no flow through the radiator, just like a closed t stat. Do I make sense?
 
Discussion starter · #216 ·
You make sense. However i was able to jamb the hose in the upper and watch it flow freely.out the lower when the lock carrier was in service position. That and the afterrun pump seems to have no issue flowing through there which i can verify with the ir gun the input side tank temp stays same and output side goes up from where it was while engine running indicating flow is happening. I believe the radiator is flowing. It wouldn't need to flow much to keep temp and the aux rad would need plugged up too. Seems unlikely.
 
Discussion starter · #218 ·
At this point I'm half ready to.just remove he tstat and remove the plates from.it and reinstall.it. In the interest of diagnotics. I'm not sure I could take installing another thermostat and having the same problem. I'm guaranteeing myself two intake dis assemblies butt. If I did a thermostat again and I had the same problem.... I might be tempted to drive this car into the Lake.
 
Discussion starter · #219 · (Edited)
I really want to Thank everybody for the help here it's been a frustrating problem . The thoughts and ideas expressed by everybody in this thread have really helped me to try and diagnose this problem. I hope i can get to the bottom of it. Especially like to thank Stephan for the same data parameters logging that I see. So I know what a normal W 12 is supposed to act and look like. I don't give up easily. I think I've shown that hopefully. But it is a really frustrating problem. Even if I junked his car. Id take this motor apart to see what the hell was blocking The water cooling. Without this forum specially the Members that belong to this forum and contribute to.it... The pointers to the self study guides. The little ideas...I would be completely lost.so. Thank you! I can only hope I can contribute as much to this Forum in the future as you all have contributed to this thread.
 
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