Body heat

[model A]

Just overhauled my 1967 bug 1600 single port engine. Now after driving a short distance I can hardly open the engine compartment without gloves the latch is so hot. Thinking the engine was overheating I have gone thru all the procedures I know ie, timing, tin and gaskets, fan and thermostat, all check out fine. I finally got a thermostat and tested the oil after a drive and the oil temperature is right on 180F. Also I've not had the engine oil light come on, so, assume the engine is ok. What would cause the compartment lid and rear deck to get so hot? The only opening I can find is the latch hole that is just above the muffler and I can't find any gasket or seal in any catlog to cover this hole. Any suggestions would be appreciated, thanks.

[crvc]

I had similar problems in my 1967 bug. Among other things I tried off-set hinges then had vents welded into the solid '67 engine lid. For me the problem turned out to be a bad oil cooler.

kevin

[model A]

Thanks for responding. Is there some way to test or isolate the oil cooler as the problem. I don,t understand as the oil temperature is running at 180 which is very good. I'm wondering if its somehow coming from the musffler althought it seems to be secure and sealed. Like I said the only opening I have is the hole in the rear deck where the latch attaches, but haven't found any kind of seal for that. Do you know of any? Thanks again

[crvc]

I'm not one of the gurus. A photo might help get their attention. One trick to use with an overheated engine is setting a tennis ball under the lid. Wiring it to the latch is how I imagine it. My problem was the oil cooler but there isn't a test. I thought pressurized air shooting in and out meant the cooler wasn't plugged. Not the case. I put in a new cooler and that instantly solved the overheating problem.

If you can hold the dipstick without blistering your fingers then the engine probably isn't overly hot. The exhaust gets much hotter than the engine so that might be your heat source? What's between the lid and exhaust?

kevin

[model A]

I can take the dip stick out, it is hot but not so hot to burn my hand. The deck latch is hotter. There is nothing between the muffler and the latch except the center body piece that the latch connector is bolted to and the hole I mentioned. Maybe a piece of tin if missing between the muffler and the body pan? Haven't seen that in any drawings. I'm frustrated. Car runs beautifully but am afraid to drive it with the heat problem. Michael

[FJCamper]

Hi Model A,

Your exhaust is probably to blame, muffler or extractor. I'd bet you're venting exhaust system heat upward.

Something is different than before your rebuild, some sheet metal or duct work.

FJC

[model A]

Hi FJC, That certainly makes sense to me. How do I check that? Muffler doesn't sound as if it has a leak or anything. I don't feel any upward flow of exhaust, but only have checked that at idle. Will try to detect anything while revving the engine. Thanks, Michael

[FJCamper]

Hi Model A,

VW Bugs have a high drag area from the rear window on down. The air flow behind the Bug is actually trying to blow against the rear end. Above is the aerodynamics of our SuperBug as we last ran it at Daytona, clocking 125 MPH on the banks. That's great for a Bug, but not good enough for Daytona.

Exhaust heat gets picked up and depending on your road speed, "pocket" inside the bumper or under the sheet metal just above the bumper. Obviously, this isn't common. That's why I said something is different after your engine rebuild. Possibly you just might have a new muffler "burning in."

Muffler heat pocketing was bad enough in the 356 Porsche that new, the cars came with a sheet metal heat shield plate over the oil pump cover. Careless mechanics tossed them over the years, and many 356's ran high oil temps -- the owners never knowing why.

FJC

[Marc]

...The only opening I can find is the latch hole that is just above the muffler and I can't find any gasket or seal in any catlog to cover this hole...

...your instincts are correct, that hole needs to be filled.

As you've no doubt discovered by now, 1967 Beetles have many unique "one-year-only" parts, and you're missing one... the P/N is 111 827 527.
http://www.paruzzi.com/webstore/?klanta ... bgroup=all
http://www2.cip1.com/ProductDetails.asp ... 11-827-527

Now, when VW first increased the displacement of the Beetle engine to 1600cc in 1970 they adopted the louvered engine lid which had previously been used on 1500cc Convertibles - and with good reason. You can putter about town and never miss the extra cooling air, but after more than a few minutes at highway speeds on a hot day the need becomes evident. The "first-cabin" solution is a 1967 Convertible lid with louvers, but they've become extremely expensive so many choose to roll their own as Kevin did - or just prop it open with the offset hinge kit or tennis ball. 1967 Sedan lids aren't exactly common either but if you find one the cost shouldn't be exhorbitant, in case you want to leave your present lid intact while you build a modified one...an alternative to adding the louvers is a "stealth" opening that's just slightly smaller than the license plate; with the plate mounted an inch or so away from the lid that'll let in the needed air too.

Of course if it's not important to you to maintain the car's "1967-ness" the pragmatic solution to both issues is to install a `68-up apron - they don't have that big hole, and then you'll be able to use any louvered lid including the later ones with vastly increased louver area....but save the `67 apron & lid for posterity, reproductions are hard to come by.

[crvc]

Even though it's a '67 I don't have that hole in the engine bay which made it difficult to visualize. Since the bug had a lot of '66 features I'm guessing it was one of the last of the leftover '66 cars rolling out the factory with '67 fenders, converted 6 volt starter, small flywheel, and eight fuses.

kevin

[model A]

Thank you all for you expertise. Its interesting to me that all the people in my area and the catalogs I most use apparently don't know about this rear apron latch cap. Also interesting that It cost $8.50 but reqires $13.something to ship. I was about to put some asbestos type heat shield between the bottom of the apron and the muffler and I may still do this after I try this rubber cap, as on a trial basis it did lower the heat tremendously. Just have to figure out how to attach it or find a high temp adhesive. Anyway glad I joined. Thanks Michael