I'm looking to setup a secondary oil cooler with a thermostat for my 3.0L conversion. I'm not planning on driving this car in Texas summers (90+) nor track - it's a street and daily driver. I'm thinking of putting the cooler in the floor of the rear trunk to draw in cool air with a fan through the engine bay lid.

Will a Mocal 19 Row 7.5" x 6" (cooler area size, not including brackets) be big enough for me? With 300-450 CFM fan on a temp switch.

Also I'm either nuts or oil cooling is expensive...there's about $200 worth of fitting/hose, $160 thermostat, and $300 cooler/fan/bracket. I'm so tempted just to run the car without the extra cooler and see how it fairs - I've seen comments from people doing the same even with 3.2L motors.

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you're not nuts, it's pricey!

Run without the cooler first. Most rear end coolers aren't extremely efficient, the best cooling is up front. Make sure the engine is running the right mixture and make sure the on engine cooler has clean fins and make sure your thermostat is working (get a new one). There's a good chance it will be fine.

Oil cooling is extremely expensive.

On cool days it shouldn't be a problem but on real hot days it gets sketchy.
Remember that the 3.2 did have a trombone cooler (basicly a loop) in the front fender from the factory.


This is a good solution if you don't want to run a cooler to the front.
http://www.914world.com/bbs2/index.php?sho...=Henry++Schmidt

On the 911s, the 3.2 had a radiator type cooler in the right front fender, only the 2.7 and 3.0 engines used the trombone. The metal oil lines along the side of the car probably help as much as the trombone (which really just served to turn the oil flow back to the rear of the car as much as cooled).

The proper lines and fittings are not going to get cheaper, and mounting one up front is the correct way to do the conversion. Especially in a warmer climate, I think you'd be best served to do it correctly from the start. If you're not going to be tracking the car, AN-12 lines should be adequate as far as sizing goes. A Mocal thermostat works nicely, and there are a variety of front coolers that you can use. A Mazda RX7 cooler was used by many, but you can look into options. I ended up using a Turbotrol on my conversion as I had one from my old 911 Targa, but they've been unavailable for quite some time.

I'm ditching the on engine cooler on my 3.2 conversion with a block off plate and just using a large front cooler. Not cheap but similar to what Porsche did on the 964 and later.

Many ways to skin this cat but there's no denying a front cooler is the most effective for cooling. It's out in the air, doesn't get heat from engine and can be backed up with a puller fan.

Thanks for the tips and suggestions. A front oil cooler is ideal but I won't be tracking. I've searched through the forum and seen many rear cooler setups (all done very nicely) so I think I'll be okay. I think oil coolers are like oil brands - everybody has a different opinion!

I'll give my idea a try and if it doesn't work I can add a cooler later. I won't lose any money to convert later with my oil line layout and I won't hesitate to spend the extra money to take care of my engine - if it is needed.

I'm a little late but I agree with Mark - try with no cooler before you do anything. My car has a 2.2 with no cooler and it has never gotten hot enough to worry about in street driving, even in 90 degree Dallas heat.

If you don't track it, I really think you'll be fine. If not, you can always add it later.

I agree with Mark Epstein. I plan to remove the engine mounted cooler and install a block off on my 3.2 and run a front mounted cooler with the proper tubing, connections, thermostat, etc. As much as I do not want to cut up the front of the car, I am sure that Scotty B. will be able to do it in a manner that looks so nice everyone will appreciate it. I want to do it right and never have to worry about it again. Best wishes.

+1 on the pricey!

I bought TWO of the coolers in the pic above and installed them behind the fog lamp vents.

With the coolers, the 12AN hose, the fittings, and the sandwich adapter, it was nearly $1000

Yet another opinion... I have a 993, 3.6 in my car since 1998 and frankly, I wish the internal cooler was still on it. That would make the size of my external cooler way smaller. Since I'm in the south and attacked by heat much of the time. I have another reason to like the pre-964 engine cooler behind #6, especially for a street car.

Liquid oil is a much more efficient conductor of heat than the oil-foam we cool in the front cooler. That makes the cooler in the original location can be smaller if it's a full-flow device. and for those who need it, a smaller auxiliary cooler is used up front. My mega cooler in the trunk takes a lot of real estate, and to make it work best without fans, I had to exit the airflow through the hood. Now, if it was a strictly track car I would do it differently. But because mine is as far as is marginally practical to build a compromise car toward trackability, so I have to include sitting at stop lights and moving slowly through town sometimes. To that end I had to add more cooling capacity either in the front circuit, or the high-pressure liquid circuit where the old cooler used to be.

I've added a sandwich-adapter above the small engine filter to further cool the liquid-oil. It's only a 15K BTU cooler but it makes all the difference, both on the street and on infrequent track excursions as well. My external front cooler cost $1000 all by itself, but it holds four quarts of oil all by itself. I'd have been happy to make a smaller system and less expensive.

The rear cooler is mounted behind the transaxle between twin exhausts. I replace them about every two years because they spring leaks eventually. But I don't have a fan on them either. It's possible to run lots of fans, but they draw a fair amount of current between them so I don't add them if I can get enough airflow to avoid it.

I know what some of you are thinkin'... add a separator to defoam the oil... more money!

Back to this thread, I'd certainly wait and see if I needed an extra cooler before adding one. I didn't need one when my car was a 2.7.

Good luck!

I'm also going to add another oil temp sensor about 2 feet from the engine outlet (AN to AN fitting with a 1/8 NPT port on top) - then put a gage in the middle console. Along with the regular 911 temp/pressure gage in the dash. Extra security!

You guys might want to rethink removing the engine cooler and adding the block off / oil filter adaptor idea.

The factory did this for a reason on the later motors that doesn't adapt well to the earlier 3.2 for street use.

For an all out race car it works extremely well where everything is running hot at consistently higher rpm range. Unrestricted oil flow is a fact of life here.

Its about flow, where and how much . If you look at the oil flow diagram for the 3.2
and go with a block off/ oil filter adaptor you now have to give the engine mounted thermostat an abortion so the housing is now a dummy unit. The internal engine mounted thermostat serves a purpose on a street engine that has nothing to do with a remote front mounted cooler because that has its own external thermostat to act as a bypass.

The adaptors below were done mainly for a metal particle problem in the later motors. They were a particle trap in the oil circuit versus the tank mounted filter outside the circuit.

Ran this set up on a race motor that later ended up in a street car. It does not work well in stop and go or primarily low to mid rpm ranges.

Don't do it in a street car.

OK- So I will have to rethink that I guess. Thanks for the advise Jeff.

I included a pic of the oil cooler bypass plate Im using. I don't plan to gut the engine thermostat. Instead of the oil cooler on the engine, it will be relocated to the front. I don't plan to have an external thermostat. The oil filter will also stay on the stock oil tank. I was told as long as I don't rev the engine while the oil is cold, I should be alright. Another advantage is the moving air that was being used to cool the engine cooler will now be redirected to the cylinders.

Disclaimer - Jeff H is 1000x more knowledgable than me about cars and porsches, I'm just stubborn

I can't imagine any reason whatsoever to ditch the on-engine cooler. Where's the up-side?

Marks type of block off is a different route. Put an external thermostat in line for cooler bypass with this one. You would be waiting an awfully long time with excessive idling to warm up your engine if you don't. You will still need to fabricate a block off plate for the back of the cylinder where the engine cooler sat.

Point noted - thanks

Different, not necessarily better. Refer back to stubborn comment above

... And sold the oem 6 cooler for $600