: '93 STS Oil cooler

04-07-09, 03:56 PM
I live in New England, lots of salt on the roads during the Winter. The three lines that feed the oil cooler were rusty and seeping engine oil. So I replaced the lines (dealer price $150.00) but when I started the car the oil cooler started leaking. It's an easy replacement, but the price of a new one is over $200.00. For the time being I put a union between the input and output lines to bypass the air-oil cooler. The oil still runs through the radiator though. I'm considering leaving the air-oil cooler bypass in place. My question is, since I live in a part of the Country that doesn't get very hot, do I need to replace the air cooler?

04-07-09, 04:01 PM
Are you sure it is for the engine oil?

04-07-09, 11:17 PM
Yes, the tranny air cooler is small and on the left side of the radiator. The engine oil cooler is bigger and on the right side and is fed by high pressure lines that originate from the engine oil filter adapter.

04-08-09, 11:11 AM
The oil cooler is inside of the right radiator side tank. It sounds to me like you are talking about an auxiliary cooler, maybe even aftermarket. I would not think you'd need it unless you are towing and then a trans cooler would be more appropriate.

04-08-09, 11:54 AM
The oil cooler is inside of the right radiator side tank. It sounds to me like you are talking about an auxiliary cooler, maybe even aftermarket.

...early N* STS and Eldos got an "outside" auxilary engine oil cooler... ;)



04-08-09, 12:09 PM
Hmm, thanks PontiacV8. I wonder why. At any rate, if the later ones don't have it and don't need it, I would say you'd be just fine leaving it bypassed.

04-08-09, 03:43 PM
Thanks, I needed a second opinion to back up what I suspected.

04-19-12, 12:28 PM
Mine is also damaged ...
what is the part number? ...

I live in France and want to buy one, but can not find

04-19-12, 10:06 PM
jakben, call Chris in Parts at Rippy Cadillac - up ^^^ in the Vendors posts. He may not be able to ship overseas, but he can advise you on the best course of action.

04-20-12, 05:25 AM

I always wondered why the early northstars had engine oil coolers and the later ones didn't. I still may retrofit one onto my eldorado....

04-20-12, 09:02 AM
All it would take would be the oil filter adapter, oil lines and radiator....................but if you don't tow a trailer, race steadily, or live on the side of the Rockies, why go to the trouble ???

The oil in these engines runs right where it should be - 200 to 230 degrees: the oil coolers in our cars, if fitted, are in the "hot" end of the radiator, so their function is to keep the oil at or above coolant temp at normal engine operating temperatures. This insures that any condensation moisture and acid vapor is boiled out of the oil and consumed by the PCV system. The term "oil cooler" is a nice buzzword, but it's relative: 210 degree oil is perfect; 250 degree oil is not; relatively cold oil is just as bad for an engine as overheated oil.

Not sure if all early Northstars were fitted with oil coolers - that seems reserved for the special order and/or towing "HD Cooling" package RPO - V03. I believe most of the cars destined for European sale had oil coolers - a steady 120 on the Autobahn is a far, far different set of engine operating conditions than plodding down the I corridor at 65 mph with its lazy engine speed.

04-20-12, 11:31 AM
I'm pretty sure my '97 Deville had an oil cooler (in the radiator side tank, not the aux cooler pictured above).

04-20-12, 02:28 PM
Now I know what one looks like, I'll have to check Alexandra for one.

04-20-12, 03:36 PM
Thanks for the information guys.

Most earlier model STS had the oil coolers fitted to them. In the salvage yards I seel a lot of them with them equipped, Eldorado's are few with the coolers. Most of the time the lines or "o" rings are leaky but That's a relative easy fix.