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Thermostat/cooling tin questions
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mainstreetprod
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PostPosted: Mon Jul 17, 2017 1:21 pm    Post subject: Thermostat/cooling tin questions Reply with quote

Yesterday I finished cleaning my fuel tank in my 78 FI and took the bus for a 5 mile drive. Engine was just warm to the touch, seemed fine- but for good measure I drove it another 10 miles at cruising speed. When I got back it seemed very hot, including extra noise from the driver side valve train and lots of smoke (nothing new, when it happed before I assumed it was residual oil that had leaked into the heater boxes burning off), but seemed worse than usual. I was able to grab the dipstick and hold it.

I got under the bus and checked the thermostat bellows (there is only one, on the passenger side). The cable was off the pulley and could not be pulled back on, flapper is stuck.

Questions:

1) is the flapper stuck in the position that would cut off air or allow it to flow?

2) Is there supposed to be a thermostat on both sides?

3) My engine has no cooling tin covering the pushrod tubes. Is this missing tin alone enough to cause overheating? Can it be replaced when there are aftermarket headers?

4) RE: the clattering sound from the valves that goes away when the engine is cool- is that leaking down hydraulic lifters, and do they normally leak down in an overheating situation?

5) What are the possible sources of all the smoke, coming out of defroster vents, side cooling vents, etc? Not that much from the tailpipe itself.
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aeromech
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PostPosted: Mon Jul 17, 2017 1:35 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

mainstreetprod wrote:
Yesterday I finished cleaning my fuel tank in my 78 FI and took the bus for a 5 mile drive. Engine was just warm to the touch, seemed fine- but for good measure I drove it another 10 miles at cruising speed. When I got back it seemed very hot, including extra noise from the driver side valve train and lots of smoke (nothing new, when it happed before I assumed it was residual oil that had leaked into the heater boxes burning off), but seemed worse than usual. I was able to grab the dipstick and hold it.

I got under the bus and checked the thermostat bellows (there is only one, on the passenger side). The cable was off the pulley and could not be pulled back on, flapper is stuck.

Questions:

1) is the flapper stuck in the position that would cut off air or allow it to flow?

2) Is there supposed to be a thermostat on both sides?

3) My engine has no cooling tin covering the pushrod tubes. Is this missing tin alone enough to cause overheating? Can it be replaced when there are aftermarket headers?

4) RE: the clattering sound from the valves that goes away when the engine is cool- is that leaking down hydraulic lifters, and do they normally leak down in an overheating situation?

5) What are the possible sources of all the smoke, coming out of defroster vents, side cooling vents, etc? Not that much from the tailpipe itself.


Wow, you have lots of questions. I'll try and take a stab at them.

1) Stuck cable. The flaps are supposed to be spring loaded in a fail safe position but if the cable can't move then your flaps could be stuck anywhere. You need to fix this now.

2) No, just one on the passenger side. There's a long rod that controls left and right side flaps.

3) If you have stock heater boxes I think you can install the missing tin. No, I don't think it would cause overheating if they aren't in place. I believe they protect the push rod tubes from debris.

4) Usually hydraulic lifters can bleed down when the engine is off for a period of time. Not when it's been running with oil pressure. Even hydraulic lifters need to be adjusted so go and do that now. When the engine is hot it expands making the valve clearances looser but hydros compensate.

5) Maybe a leaky fan oil seal?
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mainstreetprod
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PostPosted: Mon Jul 17, 2017 1:47 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

Thanks aeromech. Can the stuck flapper be fixed without removing all the tin? Edit: My flapper isn's stuck, operates freely. The cable just slipped off the pulley. The flapper rod is spring loaded. Does it hold the flappers in the open or closed position?

Last edited by mainstreetprod on Mon Jul 17, 2017 2:12 pm; edited 1 time in total
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TDCTDI
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PostPosted: Mon Jul 17, 2017 2:07 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

You may also have rodent nests on top of the cylinders. Smoke coming out of air intake vents & defrost vents is a good indication of oil leaks & overheating. It only takes a couple of days of the vehicle being stationary for rodents to completely block the air flow to the cylinders (They really like to nest on top of #3&4 cylinders in both type1 & type 4 engines.).
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PostPosted: Mon Jul 17, 2017 2:13 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

The conventional wisdom around here is that the "sled" tin (under the pushrods) serves the purpose of also making sure that the thermostat is reading the correct temperature. i.e., the sleds make sure that ambient air flowing past isn't making the thermostat think the engine is cooler than it actually is.

It certainly won't hurt to try to get the tinware in a condition to be close to how the factory designed.

If you don't have heat exchangers to support the outside edge of the tin, you could probably fab supports for the outer edges out of your own sheet stock. That is more or less what VW did on the Things that didn't have heat exchangers; there is a flat piece that hangs down to provide support.
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PostPosted: Mon Jul 17, 2017 2:19 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

1) is the flapper stuck in the position that would cut off air or allow it to flow?
Type IV (4) Cooling Flaps Closed n Open
https://www.thesamba.com/vw/forum/viewtopic.php?p=7765988#7765988

2) Is there supposed to be a thermostat on both sides?
thnx mayor ratwell
http://www.ratwell.com/technical/Thermostats.html

4) RE: the clattering sound from the valves that goes away when the engine is cool- is that leaking down hydraulic lifters, and do they normally leak down in an overheating situation?
Lifters Hydraulic or Solid ?

5) What are the possible sources of all the smoke, coming out of defroster vents, side cooling vents, etc? Not that much from the tailpipe itself.
How to stop huffing noxious fumes?(heat exchangers)
https://www.thesamba.com/vw/forum/viewtopic.php?t=613236&highlight=heat%2A
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mainstreetprod
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PostPosted: Mon Jul 17, 2017 2:20 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

TDCTDI wrote:
You may also have rodent nests on top of the cylinders. Smoke coming out of air intake vents & defrost vents is a good indication of oil leaks & overheating. It only takes a couple of days of the vehicle being stationary for rodents to completely block the air flow to the cylinders (They really like to nest on top of #3&4 cylinders in both type1 & type 4 engines.).


Any way to clean the nests out short of pulling the engine? Found nests on top of my fuel tank so it's likely.
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PostPosted: Mon Jul 17, 2017 2:24 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

Tcash wrote:
1) is the flapper stuck in the position that would cut off air or allow it to flow?
Type IV (4) Cooling Flaps Closed n Open
https://www.thesamba.com/vw/forum/viewtopic.php?p=7765988#7765988


Well, after reading that thread and checking my flappers, they were in the open position. Was hoping they were closed and the cause of the problem.
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TDCTDI
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PostPosted: Mon Jul 17, 2017 2:24 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

Remove plug wires at the spark plugs & see if you can see any nest material. If so, you can remove the tin while the engine is in the bay, but it's a PITA.

But hey, if you remove the engine to do this, it'll be real easy to remove & clean the tank properly.

I started my project by pulling the engine & checking for rodent nests because I have had to rebuild many engines due to their nests.
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mainstreetprod
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PostPosted: Mon Jul 17, 2017 6:47 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

TDCTDI wrote:
Remove plug wires at the spark plugs & see if you can see any nest material. If so, you can remove the tin while the engine is in the bay, but it's a PITA.

But hey, if you remove the engine to do this, it'll be real easy to remove & clean the tank properly.

I started my project by pulling the engine & checking for rodent nests because I have had to rebuild many engines due to their nests.



I duct taped a 2 foot piece of 5/16 fuel hose to a shop vac hose and probed the area around 3 and 4 through the plug holes. Got enough acorns and lint to maybe fill a thimble. Around 1 and 2 I got nothing at all. Obviously there isn't enough material there to cause overheating.
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williamM
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PostPosted: Mon Jul 17, 2017 7:55 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

Just the fact that that they have been there wold send me to HF for their 60?$ bore scop for a closer look.

Those thermostat flaps are diverters that move air off the oil cooler when the engine is cold. Unlike T-1 which shut down or reduce air flow over the engine.

So- would not be my first suspect.- By the way- easiest way to re set the cable and pulley is to vice grip the flaps rod and rotate to the front and re set the cable in the pulley. ACE hard ware carries that pulley for $13. so make sure it is not damaged- something made it jump out of there- also make sure you know what a good thermostat set up looks like.
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PostPosted: Tue Jul 18, 2017 1:12 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

[quote="williamM"]Just the fact that that they have been there wold send me to HF for their 60?$ bore scop for a closer look.

Those thermostat flaps are diverters that move air off the oil cooler when the engine is cold. Unlike T-1 which shut down or reduce air flow over the engine.

Does that mean that the engine may be running hot due to not enough air being diverted to the oil cooler when warm?
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PostPosted: Tue Jul 18, 2017 1:30 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

mainstreetprod wrote:
williamM wrote:
Just the fact that that they have been there wold send me to HF for their 60?$ bore scop for a closer look.

Those thermostat flaps are diverters that move air off the oil cooler when the engine is cold. Unlike T-1 which shut down or reduce air flow over the engine.


Does that mean that the engine may be running hot due to not enough air being diverted to the oil cooler when warm?


From what you said before, it sounded like the flaps were in the fail open/extra cooling position. So that should mean that your oil cooler was getting full cooling airflow.

If you attempt a boroscope vs pulling tins, make sure you can see down in there for sure that there isn't junk jammed in the fins of the cylinder walls and on top of the oil cooler and through it.
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mainstreetprod
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PostPosted: Tue Jul 18, 2017 5:41 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

vwwestyman wrote:
mainstreetprod wrote:
williamM wrote:
Just the fact that that they have been there wold send me to HF for their 60?$ bore scop for a closer look.

Those thermostat flaps are diverters that move air off the oil cooler when the engine is cold. Unlike T-1 which shut down or reduce air flow over the engine.


Does that mean that the engine may be running hot due to not enough air being diverted to the oil cooler when warm?


From what you said before, it sounded like the flaps were in the fail open/extra cooling position. So that should mean that your oil cooler was getting full cooling airflow.

If you attempt a boroscope vs pulling tins, make sure you can see down in there for sure that there isn't junk jammed in the fins of the cylinder walls and on top of the oil cooler and through it.


Haven't done a boroscope yet, but I did tak a long screwdriver and probe around the cylinders. Nothing feels soft like a nest, and a second vacuuming got nothing. I think my problem may be missing tin (see below).
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mainstreetprod
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PostPosted: Tue Jul 18, 2017 5:47 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

I suspect my problem may be related to missing cooling tin. Got a few questions about what I found when I snapped a few photos underneath:


What is this? If it's exhaust, why is so little coming out of it?

Image may have been reduced in size. Click image to view fullscreen.


What muffler fits this aftermarket header?
Image may have been reduced in size. Click image to view fullscreen.


Finally, what tin pieces do I need to buy to get this thing cooling properly?Will they fit with the aftermarket header in place?

Image may have been reduced in size. Click image to view fullscreen.

Image may have been reduced in size. Click image to view fullscreen.
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PostPosted: Tue Jul 18, 2017 7:39 pm    Post subject: Re: Thermostat/cooling tin questions Reply with quote

1978 heater box - Heat Dump Tubes with pictures.
https://www.thesamba.com/vw/forum/viewtopic.php?t=664428&highlight=heat%2A+dump+tubes

75-78 Type 4 Engine Tin
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