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mainstreetprod Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Mon Jul 17, 2017 1:21 pm Post subject: Thermostat/cooling tin questions |
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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 Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Mon Jul 17, 2017 1:35 pm Post subject: Re: Thermostat/cooling tin questions |
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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? _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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mainstreetprod Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Mon Jul 17, 2017 1:47 pm Post subject: Re: Thermostat/cooling tin questions |
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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 Samba Advocatus Diaboli
Joined: August 31, 2013 Posts: 12858 Location: North Carolina
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Posted: Mon Jul 17, 2017 2:07 pm Post subject: Re: Thermostat/cooling tin questions |
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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.). _________________ Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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vwwestyman Samba Member
Joined: April 24, 2004 Posts: 5688 Location: Manhattan, Kansas, USA
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Posted: Mon Jul 17, 2017 2:13 pm Post subject: Re: Thermostat/cooling tin questions |
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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. _________________ Dave Cook
President, Wild Westerner Club
1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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mainstreetprod Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Mon Jul 17, 2017 2:20 pm Post subject: Re: Thermostat/cooling tin questions |
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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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mainstreetprod Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Mon Jul 17, 2017 2:24 pm Post subject: Re: Thermostat/cooling tin questions |
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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 Samba Advocatus Diaboli
Joined: August 31, 2013 Posts: 12858 Location: North Carolina
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Posted: Mon Jul 17, 2017 2:24 pm Post subject: Re: Thermostat/cooling tin questions |
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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. _________________ Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.
GOFUNDYOURSELF, quit asking everyone to do it for you!
An air cooled VW will make you a hoarder.
Do something, anything, to your project every day, and you will eventually complete it. |
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mainstreetprod Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Mon Jul 17, 2017 6:47 pm Post subject: Re: Thermostat/cooling tin questions |
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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 Samba Member
Joined: August 07, 2008 Posts: 4333 Location: southwest Arizona
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Posted: Mon Jul 17, 2017 7:55 pm Post subject: Re: Thermostat/cooling tin questions |
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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 $13. so make sure it is not damaged- something made it jump out of there- also make sure you know what a good thermostat set up looks like. _________________ some days I get up and just sit and think. Some days I just sit.
opinion untempered by fact is ignorance.
Don't step in any! |
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mainstreetprod Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Tue Jul 18, 2017 1:12 pm Post subject: Re: Thermostat/cooling tin questions |
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[quote="williamM"]Just the fact that that they have been there wold send me to HF for their 60?$ 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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vwwestyman Samba Member
Joined: April 24, 2004 Posts: 5688 Location: Manhattan, Kansas, USA
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Posted: Tue Jul 18, 2017 1:30 pm Post subject: Re: Thermostat/cooling tin questions |
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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. _________________ Dave Cook
President, Wild Westerner Club
1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing |
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mainstreetprod Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Tue Jul 18, 2017 5:41 pm Post subject: Re: Thermostat/cooling tin questions |
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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 Samba Member
Joined: March 09, 2017 Posts: 313 Location: Tennessee
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Posted: Tue Jul 18, 2017 5:47 pm Post subject: Re: Thermostat/cooling tin questions |
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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?
What muffler fits this aftermarket header?
Finally, what tin pieces do I need to buy to get this thing cooling properly?Will they fit with the aftermarket header in place?
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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CarlosZ Samba Member
Joined: April 23, 2016 Posts: 319 Location: Los Angeles
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Posted: Mon Jan 01, 2018 11:32 am Post subject: Re: Thermostat/cooling tin questions |
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I’ve a similar situation where I’ve no heat exchangers, only j-tubes. I’ve been running all the cooling flaps and tins except for the thermostat and sled tins. I’ve picked up a complete spare engine with all the tins, thermostat and heat exchangers.
My question is: considering I’m currently running j-tubes, is there any point in installing the thermostat and sled tins? I’d think the open air w/o the HEs would cause faulty readings in the thermostat.
Thanks and happy new year to you all! |
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tommu Samba Member
Joined: November 15, 2011 Posts: 618 Location: L.A.
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Posted: Tue Jan 02, 2018 11:13 pm Post subject: Re: Thermostat/cooling tin questions |
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It's oily under there. Might be worth spending an afternoon with some degreaser to clean everything you can off. Engine and transmission. Although that oil isn't going to help with cooling, it shouldn't be the cause of overheating - if indeed it is overheating. Could be that you're just getting to the temperature where all that goop just wants to burn off. How's your timing and mixture? _________________ |
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