Oil Cooler Swap?
 

I am going to install an S oil-cooler on my 2002 base and have the following question:

1) Can this be done without removing, or otherwise lifting, the intake runner?

2) How many O-rings will this require? The Porsche parts diagram I have access to lists the following O-rings:
- 999-707-409-40 RUBBER O-RING 2 $1.61
- 999-707-389-40 RUBBER O-RING 4 $0.66
- 999-707-344-40 RUBBER O-RING 4 $6.39 :eek:
What is the really expensive O-ring for?

3) I will drain the cooling system prior to removing the oil-cooler. Can this be done without draining the engine oil? Does the engine oil automatically drain out of the cooler, or will it spill all over the engine upon removal?

4) What is the vacuum line connecting to the top of the oil-cooler?

TIA

(1) Yes, but you will need to pull the air tube running from the air filter to the intake.

(2) Four in total; two large and two small. Porsche has updated the numbers on these, so go with the dealer info. Last set we purchased ran about $15 for everything...

(3) Drain the coolant, you do not need to drain the oil. Before lifting the old cooler out, slide a large pastic bag under it to catch the oil and coolant that did not drain down, otherwise you will be cleaning up one Hell of a mess on top of the engine, plus you will prevent oil or coolant from getting into the wrong passages and creating new poblems.

(4) The line on top of the cooler is a water return line to the surge tank in the rear trunk. It is critical that it be reattached as the oil cooler is the highest point in the cooling system, and will be where any air will collect. That line gets it out to the surge tank.

To do this job properly, you will need an inch pound torque wrench to torque the fasteners (then only go 7 ft. lb.). While the cooling system is drained, it would also be an excellent time to swap the thermostat for the 160f unit.

On 1998 and 1999 Boxsters, I believe the oil cooler line goes from the top of the oil cooler to a tee, which then splits off with one line going to the coolant tank in the trunk and the other line going to a nipple at the oil pump housing at the front of the engine.

I saw a 1997 Tiptronic this past weekend at a TSBL event and the oil cooler had no line at all on the top of the oil cooler.

I looked at the front of the engine on a 2001 and there was no outlet (nipple) on the front of the oil pump housing. So, I think, in that case, there is only the line going from the top of the oil cooler to the coolant tank.

What is the reason for the set up in the 1998 and 1999's?

Regards, Maurice.

You are correct, the first cars (the 97 2.5L) had no line on top of the cooler, and in fact used an adaptor plate between the cooler and the engine case to mount the cooler (using even more orings). These cars have some issues with air entrapment significantly reducing the heat transfer capacity of the cooler, leading to oil breakdown and bearing issues. In 98, the return line on the top of the cooler appeared to address the air problem, along with another hose coming up from the oil pump housing, I assume for the same reasons (I have not heard another explanation). The adaptor plate under the cooler also disappeared during the 98-model year when the engine cases changed to allow direct mount of the cooler. Sometime during the transition from the 2.5L to the 2.7L engine, the line from the oil pump housing also disappeared (not exactly sure when as Porsche has often blurred these transition points) and we were left with the adaptor-less cooler mount and the single line from the cooler to the surge tank you commonly see today.

Worst part of all this is that parts for the early cars are nearly non-existent; the only replacement coolers listed are direct mount style with the surge line, none of the adaptor mount coolers without the surge line can be easily obtained, or any cases with the line coming up from the oil pump.

Just a note in passing, you cannot do one of these larger oil cooler updates on the 987 series base engine, the changed the layout so there is not enough room for it to clear. I’m not sure if that applies to all 987 base engines, but the ones I have looked at all seem to be that way.

JFP:

Thanks for the detailed explanation and for answering a question that I have been pondering for quite a while now. The information you have provided is invaluable, and certainly clears up a mystery that I thought was going to be harder and harder to clear up as the '97's to '99's become older and older.

Do you think that Porsche decided to eliminate the line from the oil pump housing because the single line from the oil cooler to the coolant reservoir is better suited for the purpose they were trying to achieve? In other words, is the one line system an "upgrade" or "improvement" over the older "two lines with a tee" version and would you thus eliminate the additional line from the oil pump housing by capping it off?

Regards, Maurice.

The early motors, in particular the 2.5L, suffered from a lot of teething issues, including hot spots in the cooling loop caused by poor circulation and air entrapment. From what I have heard, the line from the oil pump was a circulation and air entrapment bandaid that was "fixed" by altering the case castings to improve flow on later engines. If that is correct, I would not cap off the oil pump line on any engine that has it connected from the factory as you may end up somewhere you did not intend to go.

If you ever get the chance and you want to do an interesting comparison sometime, look at both the early engine oil cooler without the top water connection and the oil cooler on the Tiptronic transmission; they are very similar in layout, but I have not had the chance to see if they are interchangable.....

http://986forum.com/forums/uploads01/0021337649666.jpg

Thanks for the further clarification.

Here is a photo of the engine oil cooler from a 1997 with Tiptronic that was at the local TSBL event this past Saturday. I can't make out the part number from it completely, but you can see that it doesn't have anything coming off the top of it.

http://986forum.com/forums/uploads01...1337724768.jpg

Regards, Maurice.

I found another photo that shows the part number for the engine oil cooler for the 1997 with tiptronic. It's part number 996.107.025.05.

Regards, Maurice.

I had gone through the post. The swapping of Oil cooler is defined to be the most effective method to keep the oil content fresh and to enjoy the total benefits of the oil. I don't know about the total knowledge about these coolers. Please produce some more attachments for the more detailed view.




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