phoneman91

I was reading the factory manual for my 01 C5. It states that there is a factory engine oil cooler built into the drivers side tank of the radiator.

I don't believe that my 01 C5 has cooler lines. Were C5s only equipped with a engine oil cooler when equipped with the Z51 package? Or Z06 model?

KingTut

The automatics have a tranny fluid cooler in the passanger side of the radiator. The Z51 option added a power steering cooler but it is seperate from the radiator. There is no engine oil cooler stock or optional. The parts cd call the tranny one an "oil cooler" but it is tranny fluid that it cools.

Some, including me, have added an additional tranny cooler as that is the center of tranny problems, but I am not familar with anyone who has done engine oil cooling. I believe the engine is designed for the oil to be a certain temp and we should not mess with that.

phoneman91

Isn't it interesting though that apparently GM wanted to make a C5 engine oil cooler standard or optional ? And that four years after the C5 appeared----the factory shop manual still has reference to a factory engine oil cooler.

I have heard for years that the use of Mobil 1 oil made a factory engine oil cooler unnecessary -but I thought that it applied to C4s only.

Mr.Bill

I have never heard or seen in my FSM an oil cooler for the 2002 C5. I haven't read every page, But have been through it a few times.

phoneman91

My FSM for 2001-second volume for ENGINE TRANSMISSION, under ENGINE COOLING section 6-509, paragraph titled: ENGINE OIL COOLER states that the oil cooler is "on the driver's side tank on the radiator and that the engine oil pump pumps oil thru the oil cooler line to the oil cooler. And the oil returns to the oil filter to the engine oil block system."

I have noticed that aftermarket engine oil coolers for the C5 utilize the oil temperature fitting just above the oil filter and I wonder if this unknown factory oil cooler system does connect the same way.

Anyone have access to a comprehensive factory parts list--especially an early list from 1997? One may find the factory parts for this factory oil cooler set up.

Wouldn't it be interesting to check C5 number 1 that is displayed in the NCM in Bowling Green and see if there is a factory engine oil cooler on it?

KingTut

I found that paragraph and read it. Funny part is that under the R&R for the radiator there is no mention of removing or connecting and oil lines to the radiator - it does mention the tranny fluid lines though.

phoneman91

I suspect that the paragraph that mentions the factory engine oil cooler may be generic and not actually apply to the C5.I also noticed that there is no other mention of a engine oil cooler in the FSM that I can find. Strange that the FSM editors haven't removed it after at least 4 years of production of the C5 when my 2001 edition of the FSM was published.

And it is strange that the previous C4s have engine oil coolers and the C6 does also-but not the C5s.

racebum

wouldn't of been hard for them to do, especially on manual cars. they could just use the auto radiator on all models and run lines to the auto trans cooler for oil

the replacement radiator delco 20889 actually has the auto trans cooler line plugs cast in it and it's made to fit both the 6spd and certain years auto

spdislife

True...but if you ever decide to track your car, you'll want to invest in an EOC for the engine. Engine oil temps will climb to the 300 degree range without the cooler. Best synthetic oils will start to break down quickly at those temps. I just ran an event 2 weeks ago (with an EOC)and hit 263 on a 70 degree day pushing the car hard.

The down side to an EOC is normal driving will not allow the oil to get warm enough. Easily remidied though by blocking air flow to the cooler.

The sweet spot if I remember correctly for oil temps is in the 200-210 range based on a previous post by the C5 guru ET

phoneman91

Interesting to know that oil temperatures could get up to 263 degrees F.

I noticed in my FSM that the C5 goes into limp mode when temperature gets higher than 266 degrees -alternate four cylinders will fire to cool the engine down.

Strange isn't it-that the Z51 package adds power steering cooler but not engine oil cooler!

phoneman91

I also noticed that many aftermarket manufacturers of C5 radiators also offer integral engine oil coolers and auto tranny coolers in the same replacement radiator!

spdislife

Is that coolant or oil temps.