Hi,

I just changed the oil for the first time by myself in my 91 WS6 formula with a 5 speed. This thing is really rare. I decoded all of the RPO codes and the only thing that makes it short of a true 1LE is the air conditioning and the absence of an aluminum drive shaft.
The car is supposed to have a factory oil cooler, RPO code KC4. I did not happen to notice one. I am used to seeing them on motorcycles so I don't know where it would be located on our cars. Could somebody tell me where it it could be?
Also, according to the manual, the engine is supposed to take 5 quarts of oil. It was at the full line way before then. I made sure that the oil had drained, and after four and a half quarts it was overfilled by a little bit. The car has 109000 miles and I put in mobil 1 fully synthetic 10W30 that was designed for high mile vehicles.
I have only had the car for about 3000 miles. When I bought the car I changed the oil in it with a mobil 1 5W30 synthetic blend. I had this done at a shop, because of bad weather where I live. After that the car was blowing some blue smoke after it had been sitting for a bit and I had just started her. I assumed that this is due to bad valve guide seals, because the car does not seem to consume oil under load, or while driving. In fact I have not had to add any oil to it in the 3000 miles I have had her. How bad is it if the crankcase is overfilled by about a half a quart? After having changed to the fully synthetic mobil 1 10W30 for high mile vehicles, the car still blows some smoke upon start ups, but not as much. Is this something that I need to worry about?
I also have 95 firebird v6 with 200000 miles, and I have owned that car since it had only 30K miles. I have only put mobil 1 fully synthetic 5W30 in it, and that thing does not burn a sip even to this day.
How big of a problem do I have in my 91 formula?
Any help would be appreciated.
Thanks,
Anatoly

91 firebird formula WS6
LB9 305 w/l98 cam from the factory,
5 speed Borg Warner World Class
4 wheel disc brakes.
Eibach lowering springs, lowered 1.5 inches
3.42 posi rear end.
MSD ignition and wires
muffler eliminator
dual cats from the factory
K&N cold air intake
under drive pulleys
According to the previous owner, the car ran 13.8 in the quarter mile.
I have never drag raced her myself, and don't intend to abuse her, but she had no problem keeping up with a 90s M3, a 90s porsche boxter, and she smokes the hell out of my friends Audi A6 2.7T automatic.
P.S. Going past the 140 MPH speedo is never a problem either.


Thank You in advance. Any help in resolving these issues would be appreciated.

 

The oil cooler is located between the block and the oil filter. It's what you screw your oil filter to.

Your oil filter should hold about 1/2 quart of oil. If you didn't fill it first that could be why you were "full" at 4.5.

Overfilling oil is not a good thing. You start whipping that crank through too much oil and it'll fill the oil with air bubbles. Air bubbles don't lubricate.

Sounds like you could use a valve job. But i'd just run it with your synthetic for a while and see if it cleans itself up. Who knows how well the previous owner took care of it or if they were religious about the oil changes.

Not gonna abuse her at 140mph?

 

I dont think he needs a valve job at all, about 20 dollars worth of valve seals and such should do the trick.

 

I don't understand how not filling the oil filter first will make my engine full at 4.5 quarts. It would seem that it would be the other way around. I installed a new oil filter when I changed my oil and did not fill the filter first.
Could some of the oil be left in the oil cooler?
Should I attempt to drain a little bit of oil?
The oil level is about 1/4 of an inch above the operating range.

Thanks,
Anatoly

 

The factory oil cooler circulates coolant through a sandwich adapter between the filter and the block. There's no oil cooling radiator like you're used to seeing on a motorcycle.

 

just curious how well do those sandwich style between the filter and block coolers really do?

 

Liquid-to-liquid cooling is more efficient that air to liquid- doesn't require as much surface area. However, I agree that the factory setup doesn't look like it would do a whole lot to me. Better than nothing, but probably not enough if you're going road racing or other events where the motor will see high RPMs for extended periods of time.

I does have the advantage that in cold weather the coolant will actually help to WARM the oil more quickly than it would on it's own (coolant reaches full temp much more quickly than the oil does).

Maybe somebody will chime in with some actual "back to back" testing results with and without the factory cooler.

 

That's the majority, if not $$$, of a valve job.
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You never stated if you started the car before or after checking the oil level.

Did you?

 

The majority of a valve job is grinding and lapping the valves and seats. If you're not doing that, you're not doing a valve job.

 

I added 4 quarts of oil to the engine and then I started the car. I let it run for a minute and shut her off. I waited a few minutes and checked the oil level. It was in the operating range. However, knowing that the car is supposed to take 5 quarts, I was a little bit worried that she might be low. I added another half a quart of oil to get it to the full mark. Now it is about 1/4 of an inch above the full mark.
I am just wondering where 1 quart of oil would have gone in the engine, since that engine seems like was full after 4 quarts.
Another concern is that the previous owner had mentioned something about having broken off, and then replaced the oil dip stick tube. I am just wondering if maybe the new one that he had installed was not calibrated correctly.
Is there another way of verifying engine oil level?
I don't see any air bubbles on the dip stick after the car has been run.
Thanks

 

Okay then let me just say that if you're at the point of replacing the valve seals, then there's very little work left in getting to the rest of the stuff, assuming the heads are off. The assumption. I see where you're coming from Apeiron.

Replaced the dipstick? There are different part numbers on and the length is different between the dipsticks on my 88 Formula and 92 GTA. Go figure. My 88 Formula came with a 305 and I replaced it with a 355. The oil level with the 305 dipstick always read full on 4 quarts which I know to be crap. I just remarked it at 4.5. 15000 miles later and no problems yet.

 

The dipstick is hardly a precision measuring instrument. Don't worry about whether it took 4.6L or 4.5L, or whether it's just a little too high or just a little too low. It really doesn't make much difference, as long as it's not way low that the pickup starts sucking air, or way high that the crank starts hitting the oil.
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Yes, but the heads don't need to come off to replace the valve seals.

 

where is the liquid to liquid part? if it is being cooled by the engine coolant then that wouldn't be much better then air to liquid as the engine coolant is warm and wouldn't present as much of a temp differential vs air to liquid

 

The difference in efficiency between air-liquid and liquid-liquid can still be great enough that warm coolant is still better at cooling than cold air, but coolant is closer to the desired oil temperature than air is anyway.

 

wouldn't have though so on that one. I guess I could be wrong though. that and most people seem to prefer front mount oil coolers if they can fit them it seems.

 

Not many street cars need an oil cooler, unless they're turbocharged or something. The biggest benefit to the factory oil cooler is probably the faster warming of the oil on cold starts.

 

Here are photos of the factory oil cooler on a L98. Arrows indicate coolant supply and return pipes.
Also as Apeiron said: The dipstick is not a precision device. If either the dipstick itself or the tube have been changed then neither one can be trusted to read correctly. Suggestion: Drain oil completely. Fill with correct amount of oil. Run engine. Mark dipstick to indicate full at that level. (this suggestion is of course, not meant for aftermarket stuff)

 

Thank you for all your help.
I guess I will remark my dip stick.
Anatoly

 

I had the engine out on my 90 5.7 for some engine work. my oil cooler pipes were starting to rust through (after 17 years). Although I did get replacements from GM, I decided to delete the oil cooler at that time.

I don't have a engine heat problem, but then again, It's not seeing prolonged hard use either (e.g. road racing, police interceptor, etc).

 

They were starting to rust through? Mine are aluminum.

 

You dont pull the heads to replace the valve seals, its a job accomplished in a few hours. In order to do a valve job, you mush resurface the valve seats (3 angle grind) and you mush regrind the valve face. You must also reground the valve tip and re-chamfer the valve tip. Most builder then like to hand lap the valves, unless the do an interference valve grind, even then its better to hand lap. this requires the heads to be removed and completely disassembled, a big difference from replacing valve seals, which as stated above, would cost him about 20 bucks and a few hours of time.

 

Assuming the heads are off.

That's in the quote you used from me.