OK Im not a mechanic. Im also confused by reading and some mechanics reactions and advice. I have a 86 4+3 manual spd. convertible w/aluminum heads. Does this car come with an oil cooler and is the oil cooler and transmission oil cooler the same thing? According to the RPO codes an oil cooler should be "KC4" and I dont see that on my car's codes.

The problem: The oil temp sky rockets at normal RPM driving speeds. It keeps rising and rising especially if the ambient temp is hot. If I slow down, the oil temp creeps down. The temp never seems to level off and keeps climbing till I reach 260+ and usually pull the car over. I cant drive the car for more than 20 mins or 10-12 miles which ever comes first. Water temp runs 214-220F if memory serves...

I replaced the oil sensor, run Mobil1. The car was modified (rebuilt) for HP years ago and never ran right. Has less than 2k on rebuilt engine.

It also has a hi-flo oil pump (but no hi-flo pan). The oil pressure runs between 72-80 and never below.

Now the car wont even pass emissions. I'd like to drive my Vette w/o these limits and oil temp problems.

Any ideas? Everyone is stumped.
Steve

 

The oil coller is a option . It will take 5& half quarts of oil if you have one. with the cooler my oil runnes about 20 deg. higher then the water temp IOn the glove box lid there should be a builted sheet

black 88

 

The KC4 oil cooler sits immediately between the engine block and the oil filter (it's what the oil filter screws into). It should have two lines/hoses coming into it. The lines/hoses deliver engine coolant to the oil cooler. The theory is that the oil temperature (under normal conditions) is hotter than thecoolant temperature and therefore the engine coolant willlower the oil temperature.

That's great if you're moving and the coolant temperature is running normal but sitting in stop/go traffic in Houston, TX during rush hour in 90 degree plus temperatures is an entirely different story...

I could be wrong but recall that Chevy eliminated the KC4 oil cooler from the C4 in 1993 (?) when they started running synthetic oil as synthetic oil runs cooler and the oil cooler wasn't needed (plus it eliminated about 7 pounds from the curb weight of the vehicle).

To be honest with you, as I run Mobil One oil, I've considered simply removing the KC4 oil cooler from my 1990 Corvette as I have an oil leak in the vicinity of the oil cooler and think that's where the leak is originating.

 

This is not going to help but the oil cooler was dropped for the 1992 model year, thats when GM started using Mobile 1 in the LT1.

 

Steve,

What did they do to the engine 2000 miles ago? Can you post the emissions test numbers? Oil gets really hot for three reasons: Friction, excessive pump pressureand combustion blow by. When you say it never has run right since the rebuild.....what do you mean?

-John

 

The engine was rebuilt and modified for HP gain. Nothing crazy as the engine LOOKs stock. Heads bored out etc etc. The car always seemed to run up oil temp and oil pressure and the over drive was not properly reinstalled, so it doesnt engage. The car has power and runs smooth, sounds smooth but has the problems mentioned.
Finally, I talked to the guy who built it years ago. he said to replace the oil pump with a standard one and take out the Mobil1 and use 10-30. He recommended an oil cooler which I dont think this car has.

 

Steve,

Sounds like thecar has more than one issue with it. Flunking the emissions test is one set of issues, the oil temp may be another and the overdrive is the third.

While I support replacing the oil pump, that is a real pain. The only advantage is that you could also deal with the overdrive at the same time.

Based on the other posts, I would like you to check for the presence of the KC4 oil cooling setup described. I'm wondering if during the rebuild process someone disabled the oil cooling system. Depending on what you find we can go from there.

In regards to you friend's comments: Mobile 1 handles heat better than a standard oil. More likely than not he is thinking that a standard oil will thin out and lower the pressure a bit.

There isn't a whole lot to screw up on the overdrive.....did he rebuild it?

-John

 

RE: emissions; the o2 sensor will be replaced.
RE: oil temp; I will check to see if there is a oil cooler. But based on RPO codes, I dont see a code for it. But I do have a code for a B4P - Radiator cooling boost fan, whatever that is.
RE: Overdrive; I know nothing about this unit. When i took the car to a vette specialist in 2000, he said there were parts MISSING from the drive. Thats why it didnt work. My milage now sucks average 9MPG! I was getting 20MPG+ before the rebuild. Are the parts readily available for the overdrive trans?

 

Heads don't get bores out. Maybe the cylinders. Heads get shaved. Somethin's else is wrong here, anyway. The mechanic put a rebuilt motor in front of a bad tranny?

The descriptions of what's going on here aren't really clear...

Don't worry about the O2 sensor right now - there's bigger problems goin' on. The O2 sensor failure is the biggest myth in the consumer's minds'. More on that later.

You've been drivin' your car for 7 years without an OD? At highway speed it's no wonder you're runnin' hot. Super hot oil + high pressure = leaks, and a dead motor.

Your O2 sensor does not even function until the motor reaches operating temperature. When it does function (at 600 degrees), that is, start to send info to the computer, itSTILL does so very little to change the burn, UNLESS THERE IS ALREADY SOMETHING WRONG IN THE MOTOR. If the motor is properly tuned, the O2 'reads' the exhaust, and sees that no air/fuel 'correction' is necessary.

It's like quality control on a doughnut assembly line. The doughnut checker sees doughnuts start to come off the line with no holes, and he says "You're usin' too much dough - stop the lines."

Ya think the hole-cutter might have a problem? Your O2 sensor has the final say in the mix, just like the doughnut checker. Itwill override input from other sensors.

What parts?

 

CWB; if you give me your email, I can send you a pic the engine's work order and a pic of my RPO codes. I dont know how to do it here. As I said, Im not a mechanic. Im trying to peice to gether years of things ppl have told me and what Im experiencing and when... my email: illstudio at snet dot net
thanks STeve