Oil Cooler on 87 Coupe

[al@broadway]

I recently changed the flexible pipes on the oil cooler of my 1987 3.2 Coupe, in so doing I had to remove the oil cooler and drain it. I noted that the oil was looking 'well-used' as compared to the oil in the engine which is new. It occurs to me that in a normal oil change the cooler will not drain, but of more concern is that it appears that the new engine oil, changed 1000 miles ago is not circulating the cooler.
Is this normal, does the oil only circulate the cooler when it reaches a certain working temp?
Should I have replaced oil in cooler as I was relying on the pump to replenish and I would top up accordingly in the normal filler.
Perplexed Alan

 

[Chris_911]

There is a thermostat in the oil lines to the cooler - so that part of the circuit will only flow above the thermostat temp.

The thermostat is located at the forward end of the driver's side rear wheel arch (on an RHD car). It's easily spotted.

For an oil change there is no practical way to drain this part of the circuit. The danger with remaoving the oil cooler is the very real risk of fracturing the two pipe unions - and you don't want to do that when you realise how much a new oil cooler will cost.

 

[al@broadway]

Thanks Chris,
The oil is not reaching a temp to open the thermostat, obviously not driving it hard enough!
What is the capacity of the cooler? I think it must have been about 1 litre?

 

[ClubSport 911]

any decent garage will get the car hot prior to the oil change (thus ensuring the thermostat is opened) so that the oil from the cooler is drained.

It might be worth checking this out yourself next time your car is for it's service

 

[nathan 1981 930 G50]

It would be a miracle if the oil drained from the front cooler doing that unless that car was hung up from a crane or something []

To answer your question Alan the cooler holds so little oil that it would not cause any harm to your engine when the cooler is eventually refilled. It would have been a good idea to fill it up before refitting but even I did not bother and I tend to be over the top. I always fill oil filters on other cars when changing the oil & filter as I worry so much []

 

[al@broadway]

Thanks for the re-assurance, I'm carrying a can of oil with me and watching the gauge diligently but I guess it will be next summer before the thermostat will open, (assuming we have anything approaching 'normal' weather!)

 

[Chris_911]

Al

I can't believe that your oil is not getting to the thermostat temperature. Sounds like your thermostat may be faulty?

Are you saying that the oil cooler circuit pipes remain cold however long the engine is run?

I believe the thermostat stays shut below 83 deg C.

 

[Big_nige]

the thermostat should open up pretty much within 5-10 minutes of normal driving. You can usually tell when its happened as the oil level gauge becomes more active/higher level.

 

[al@broadway]

I drove to Castle Combe on weekend, approx 50 miles each way and the pipes to the cooler remained cold. The oil temp however, only reaches the first white graduation on the gauge.

 

[l2015]

On a similar note,I noticed at the beginning of last summer after i had flushed and drained the oil that a certain amount of black sludge remained in the bottom of the oil tank.As i had not had the car that long and as the engine had recently been rebuilt (3k earlier) I knew that the engine would be clean internally. I decided that when the car was going off the road for the winter I would remove the oil tank , hoses pipes and front cooler and clean the whole lot. This also gave me an opportunity to repair the underseal in the kidney bowl area where the in line thermostat resides and also allowed me to clean and repaint along the entire line of the oil pipe run . ( I'll wager this is a common place for corrosion.)At the moment tank, pipes ,front cooler are all freshly painted awaiting re fitting.

 

[nathan 1981 930 G50]

ORIGINAL: al@broadway

I drove to Castle Combe on weekend, approx 50 miles each way and the pipes to the cooler remained cold. The oil temp however, only reaches the first white graduation on the gauge.

Sounds familiar.

If you want it to open then just let the car idle.

 

[nathan 1981 930 G50]

ORIGINAL: l

On a similar note,I noticed at the beginning of last summer after i had flushed and drained the oil that a certain amount of black sludge remained in the bottom of the oil tank.As i had not had the car that long and as the engine had recently been rebuilt (3k earlier) I knew that the engine would be clean internally. I decided that when the car was going off the road for the winter I would remove the oil tank , hoses pipes and front cooler and clean the whole lot. This also gave me an opportunity to repair the underseal in the kidney bowl area where the in line thermostat resides and also allowed me to clean and repaint along the entire line of the oil pipe run . ( I'll wager this is a common place for corrosion.)At the moment tank, pipes ,front cooler are all freshly painted awaiting re fitting.

I am doing my 930 tank at the moment. I had my 911 tank cleaned a long time ago.

I recommend that people do this as the oil is unfiltered going to the engine. Condensation at the filler neck causes crud to build up. This crud gets loosened and put into the tank when oil is topped up or replaced during a service.

It would be a good idea to redo this every 10 years as well.

 

[al@broadway]

ORIGINAL: nathan 1981 930 G50

ORIGINAL: al@broadway

I drove to Castle Combe on weekend, approx 50 miles each way and the pipes to the cooler remained cold. The oil temp however, only reaches the first white graduation on the gauge.

Sounds familiar.

If you want it to open then just let the car idle.

Thanks for the tip, Nathan. I let the car idle for approx. 20 mins and the stat opened up OK, oil cooler filled OK, no leaks on flexis, thank God, added an extra half litre and everything's fine.

 

[l2015]

cant argue with that nathan,no point in putting clean oil into a dirty tank.liam