Engine Cooling

[Mike]

I took a run from Salt Lake City to Yellowstone for the Yellowstone Rod Run the first of August.  The car ran pretty hot.  When I returned home, I purchased the How To Keep Your VW Alive bug bible. 

 

It indicated that the engine compartment sheet metal had to be in place for proper cooling and the local bug shop concurs ($800). 

 

Fiber Fab said not so.  Just change to Porsche parts.  ($2,200)

 

Any thoughts from the Great Collective?

[Royal]

I’d like to help but need to know more about what you have.  What engine?  Stock or modified?  What was the temperature of the engine oil/cyl heads if you know?  What causes you to say pretty hot (is this your first air cooled VW)?  In absence of the above info, I would say that many of us run VW engines with no overheating problems.  I live in New Bern NC and my engine oil temperature high all summer was 200 degrees.   Most all of us have almost all of the original tin in place.  It is particularly important that you have the tin that surrounds and is between the cylinder heads.  Make sure that your thermostat is functioning.  It may be likely that your engine is just really dirty, especially around the cylinder heads.  Just a very thorough cleaning did wonders for me.  Also, my engine came with 50w oil in it.  Prior owner reasoned (wrongly) that it was an old engine and heavier oil would be better.  The oil was so heavy that the bypass around the oil cooler was lifting thus bypassing it.  I put 10w30 oil in and my engine temperature went down about 25 degrees (I have an engine oil temp gauge and also an infrared gun to check my temperatures.)  I have never heard of a Porsche parts fix to overheating problems.  

[edward ericson]

Define “pretty hot.”

[newkitman]

Its always good to have all the correct engine cooling tiin in place. VW spent a lot of $$$ in aero engineering and testing in their design back in the 70s. Two big improvements were the larger fan and the offset (doghouse) oil cooler. A lot of owners of the earlier VW engines went to the doghouse cooler. It repositioned the cooler allowing the fan to pass more air down between and around the No. 3 and 4 clyinders. The older style had the cooler blocking a good portion of the air for those two cylinders and the resultant temp was higher.

The reason a lot of folks say to separate the air on top from the air on the bottom is that the hotter air is lower and separating the two areas prevents letting hot air get injested into the engine. BUT…there are more things than oil that makes an engine run hot. Too lean a mixture can be just as bad or worse. I’d say Royal is correct. Give your engine a thorough cleaning, fresh oil, adjust the valves, and give her a tune up. And make certain the thermostat is there and working properly. If you do that I think you’ll notice an improvement in engine temp.

Allen Caron
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The Shack

[edward ericson]

Don’t think you need to spend $800 on type 1 Beetle tins. Check the Samba classifieds. These items go on with little screws, sheet metal, etc. You’ll see when you do your cleaning.

[Mike]

Thanks for the feedback. 

 

I defined hot as not being able to grab the dipstick.  There was almost no sheetmetal arond the engine separating upper and lower and, of course, the TD engine compartment leaves a lot of holes aroudn the stock tin soo my shop said he will cut and fit pieces to fill the holes and build a firewall in the front (as defined by John Muir) of the engine. 

 

I have hydraulic lifters so valve adjustment isn’t a problem but would like to know it I should time her for 5000 feet of altitude. 

 

I have a brazilian dual-port.

[edward ericson]

Dipstick test is probably good, but my old mother could always hold much hotter pots then me. A meat thermometer set down in there will give you better data. 220 F is still OK.

Yeah on the separate-top-from-bottom job. Should not be too hard. At 5000 feet you’ll probably want to lean the mix a tad to account for the thinner air. But running it at sea level settings should not have made it run hot. 

[Mike]

But the engine compartment on the kit car isn’t shaped like a beetle . . . so . . . big holes.  I broke down and used BC Autowerks in Ogden UT.  They provided stock parts and some creative handcrafted parts for the gaps and the . . .  what? . . . firewall?

 

Now my fuel doesn’t boil and I can check my oil.

 

Thanks for your feedback.

[edward ericson]

There you go!

Sheet metal and pop rivets have been a way of life for me 35 years running.

[Marc Lipsius]

I have the lower tin in place, and have closed off the small gaps between it and the body with tape (have been looking for high temp foam), and made a crude firewall out of a piece of galvalume sheet metal roofing material cut out here and there so the carb throttle cable and the fuel line pass through, screwing that into the fiberglass of the body at the front of the engine compartment.
I also have a doghouse cooler.
My engine temps have dropped 20 degrees or so measured with an infrared thermometer before and after I put in the firewall – no matter the outside ambient temps. It seems counter-intuitive that the engine temp would be less with the firewall blocking all the “cooling” air coming into the engine compartment from underneath the car, but I have measured it multiple times, and it truly is. I just spray painted it black so it’s less obtrusive and kept it screwed into the front of the engine compartment in case I ever wanted to or have to remove it. It’s easier than having to remove pop rivets.
Just make sure you have nothing blocking the fresh air intake into the engine compartment (like a spare tire cover) or the front of the fan.

mrlmd2012-10-17 17:20:24

[Hugh Coffey]

You need to make sure that the cooling vanes are in place even if you don’t have a thermostat. I have the stat will reduce engine wear by warming the engine aluminum parts expand to operating temp faster. The separating of the hot and cold air is a necessity, the Germans separated them for a reason. My oil temp never gets over 190 degrees. These kits were made for simple “Boy Toys” not for long distance. Also make sure that there is sufficient air intake for cool air. In short, if you over seal the upper, not enough fresh air will be there. Sounds like you are on the right road. I made my fire wall and other sheet metal out of Aluminum. It is a cheap way out and looks pretty good. I also suggest painting it black to keep it from reflecting heat.

Good Luck. 

[Author]

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