'74 Targa Overheating

So I’ve got a little overheating problem in my 1974 2.7 Targa. From what I gather the overheating was/is a chronic problem with the 2.7 models. Before I head down the route of adding an external oil cooler I thought it might be a good idea to see if I’ve covered all the bases. This problem has existed as long as I’ve owned the car – i.e. it’s not something new. I typically don’t drive it on long enough trips for this problem to make a difference – but now I’d like to!

The engine is stock, it’s got a new distributor and new plug wires – timing and ignition system checked and double-checked. Valves are adjusted. It runs great! It’s been “rebuilt” at least once, but I don’t have all the details. It leaks some oil, but does not appear to be burning any. I added the “numeric” temp gauge and on any given day if I run the car harder – say 70+ mph up a long hill - the temp will climb up to and sometimes go over 250 degrees – which I know is way too hot. When I go back down the hill the temp goes down – but not very much and if I go back up the hill the temp gets even higher by the time I get to the top. The problem is the same on 70-degree days and 100-degree days. The car has only the engine mounted oil cooler – there is no “trombone” cooler. Also, there are no “reactors” and no air pump.

Question is: What else if anything should I/can I check? As I said, it seems to run fine – apart from what I suspect is a leaking check-valve in the fuel pump that requires me to leave the key on for about 15 seconds in the morning before I start it. Could a weak fuel pump – lean mixture - cause this problem or should I just bite the bullet and get the external cooler?

Any ideas would be greatly appreciated!

Thanks in advance.

Mike
mike@telamon.com

I sugest u get an external oil cooler anyway.
But a lean mixture will make the car run hotter.
I had every thing checked, with an external oil cooler but my car would still run hotter than I´d like. The problem was a oil tank completly covered with oil and dust, a thick layer all over. After cleaning it, the temps are realy cool. Before it would hit 250° in traffic, now 220°.

To quote Bruce anderson in the latest Excellence "Most 911's have adequate oil cooling for normal use, but the 2.7-liter cars with no external oil coolers may have been the exception, particularly in hot climates". (Technical Notes, Oct 2000)

Hi All,
I have a 74 911 Targa as well. I had the same problems and you only solution is to put on the external cooler. If you are mechanical it is really not that hard and it is an instant cure for the temp problems.
Mine ran as hot as your and after the insatllation I run under 210 ALL of the time. I put in a scoop with a hose that directs air to the radiator cooler and that has helped bring the temps down an additional 10- 15 degrees.
I have it on my web site at :
http://members.rennlist.com/5150targa

and there is an artical at :
http://www.pelicanparts.com/911/911tech_articles.htm

under External Oil Cooler Installation.

If you have any questions just email me.

Tom Sharpes http://members.rennlist.com/5150targa

Hello Pacerville,

It sounds like you are aware of this, but just in case, what is your oil pressure like?

My car is very worn now and doesn't hold good oil pressure - over the past year on hot days its been prone to running hotter than ever before - probably from bearing heat and inadequate oil circulation.

Also, I'd definately try to get that fuel problem fixed - a sure sign of a lean mixture is a hot engine!

Finally, a good steam clean underneath the engine will remove any dirt and oil deposits that tend to clog up the cylinder fins and oil tank - your engine and oil circuit surface area is precious and you may as well make the best of what there is...

But, having said all the above, it sounds like your car is not unusual, and fitting additional cooling is probably the way to go...

Good luck,

- roGER