This is a long one, but please bear with me.

To review, when I get into stop & go traffic, my oil pressure starts creeping down to just below 30 psi, according to the gauge. In the past week, I have done another oil and filter change (from M1 10W-30 to Castrol 0W-30, same model M1 filter), which gained me a few psi across the board, but I'm still a little nervous.

Saturday night I got home from a 45 minute freeway drive. Oil pressure was holding strong at just over 40 on the gauge, so I decided to do a little experiment. I pulled into the garage, left the A/C on, and let the car idle while I cleaned the windows inside and out (they were getting scummy and I needed something to do to pass the time). After about 20 minutes, I checked the gauge and sure enough, it was down around 30. So I popped the hood and checked my fans. The driver's side fan was spinning at low speed (presumably to blow across the condenser for the A/C), but I couldn't see the passenger side. I shut off the engine, went inside for about 5 minutes to find a mirror, then came back out and put the mirror under the car, where I could see the reflection of the passenger fan.

When I started the car back up, I heard the fans kick into high for about 30 seconds, then they cut off. I turned the A/C back on and the driver's side came alive, and I THINK the passenger side was on low. The oil pressure was at about 35 on the gauge at this time.

So the fan question is: When should the fans go to high? I don't have LS1Edit or a Predator/Hypertech/etc., so I can't get an accurate temperature reading, but I know the fans aren't getting into high when I'm in traffic, because I can hear those suckers when they're going full speed.

If it turns out that an engine temperature problem is causing my oil to break down (and thus the pressure to drop), what would be the best way to diagnose this?


Thanks.


-Mike

 

TTT...I think I'm having the same issue. At night when the temps are cooler my psi doesn't drop as much.

 

Happened to me today! Anyone have any ideas?

 

People say its the oil pump going out or a bad o-ring, but I'm still not sold on that idea. I think it has to do with temperature. Down here we have temps in the 90's, I was thinking of maybe adding an external oil cooler.

 

Temp actually not that bad today. I have the LS6 Oil Pump, a 160 Stat and an SLP radiator. Hot day here I barely get over 170, She shot to about I think it was around 220? and oil pressure dropped to about 30 when I usually get 50-60. For no reason Temp went through the roof and oil pressure dropped. (I way idleing with A/C on) I think the fans might be the problem. Maybe not coming on full blast when needed? I never had this problem at all. Once I hit the highway, temp dropped fast and oil pressure went back up? Wierd.

 

Good to know I'm not the only one seeing this. Although, I guess in a way it's bad that I'm not the only one seeing this.

Anyone want to help us out? The idea of running an oil cooler is a nice band-aid fix, but we shouldn't NEED to run an oil cooler. Lots of f-body drivers live in Houston, and I know they're not all running oil coolers...


-Mike

 

You really don't need any more oil pressure than is absolutely necessary. At an idle that sounds fine. I doubt that your oil is breaking down. Then you'd have other problems that'd show themselves in all kinds of ways. It's damn sure not an oil pump or a bad o-ring! Usually as oil temp climbs, you will see a lessening in the oil pressure, but that's not bad. In fact oil temps play an important part in horsepower, but there's a limit.Synthetics can take an incredible amount of heat. A synthetic race grade oil can take a temp of over 300 degrees for an amount of time If you're not running a synthetic oil, I'd strongly recommend it. I'd have your guage checked for accuracy, but I doubt that's it. I would recommend an oil cooler. A factory OEM unit would be just fine. I bet then, that you would aleviate some of the problem. Also, when's the last time you have done any cooling system maintenance, like flushing the entire system and going with new coolant? Stranger things have had simpler solututions. I'd recommend Evans.

 

Sawedoff: I appreciate the input. I had the coolant flushed about 3-4 months back. I am running Castrol synthetic 0W-30.

As much as I would like to believe everything is OK, the fact is the pressure didn't act this way a year ago. I didn't have to run heavier oil before to maintain good pressure, and I didn't burn near as much oil until a year or so ago. Something has changed, and I want to fix it. As a daily driver with 80K miles on her, I know some parts are just going to wear out, and I'm fine with that. I bought her to drive her, and I'll keep driving her until I can afford to put her in the garage and start a total rebuild.

I ordered the Helm manual yesterday, and am going to look into putting a mechanical gauge on, to get an accurate reading. Once I have a better idea what I'm up against, I will post up some details, to see if anyone has any ideas.

I'm a computer geek, not a mechanic, but I'm willing to learn. Trouble is, I have to pick my battles carefully, as any major work I start has to be finished by the next business day, so I can get to work! If I don't get to work, I don't have money for mods!


-Mike

 

Well it isn't your oil, because I've been using Neo Synthetic race oil in 0w-5 since my car was new. Your engine got hotter at idle in the garage because it's not getting the same amount of airflow through the radiator irregardless of how the fans are running. That elevated temp in and of itself will heat up the oil. My car is factory 99' Z28 1LE, and I have the OEM oil cooler. It will definitely do the job! I'd almost be willing to bet that it's the valve stem seals. They do become hard over time and your consumption will go up when they're bad.

When you get a guage hooked up for temp readings, just remember that synthetics can run at hotter temps without the breakdowns like conventional oils. 220-250 degrees is fine. They can even get into 300 degrees without any probs. Good Luck.

 

Interesting idea. Occasionally, when I hit the accelerator, I get a lot of vavletrain noise. Kinda like someone threw a bag of marbles in the valvetrain and they rattle arround. A little more gas usually makes them go away, but I can get them pretty consistantly under heavy load/high rpms. I know a lot of our cars do this, but if it is contributing to the oil problems (and I know sometimes it's just bad gas), then this might be something I really want to look at.

Is it possible the two issues are related?


-Mike

 

Valve stem seals are inexpensive little doodads.It wouldn't cost an arm and a leg to fix (valve stem seals). Heck it may even be valve guides. If you're burning oil, then you are losing horsepower. You may very well be denotating, as oil upsets the A/F ratio mixture because it burns at a different rate than fuel.That may be what you hear that sounds like a bunch of marbles.It's not something that would go away with more throttle. The engine noise just drowns it out, that's all. I would look into that. It's something minor that can be a major pain in the ***. I wouldn't even think that your rings are bad, because it's not that at all. Also, I would look at your spark plugs, that will tell you some of the story about how the engine is doing.

 

I changed the spark plugs back around February, when I first noticed the consumption issue. All 8 were worn, but not wet. I also haven't seen any exhaust smoke, though the cats may be masking that. Still, dry plugs and no smoke lead me to believe my rings are probably OK.

Is there a way I can check the vavle stem seals, or is that something I would just replace and hope fixes the issue? HOw hard are they to change, and is it something I could do in a weekend, or should I take it to a shop?

You rock!


-Mike

 

There is one way that you can go about checking the valve guides, and that's with a leakdown test. They are simple to do, and a shop would have no problems in doing that. Find an honest one, not some dude that's going to feed you alot of hype in order to peddle his hopped up heads on you by telling you info that's not true. The leakdown test is a measurement of how much pressure a cylinder can hold. It is a good diagnostic tool for checking all kinds of things. Here's a place that sells a good unit: http://www.longacreracing.com/catalo...d=830&catid=17

You would want to look at the plugs for other reasons. You are looking for signs of detonation. Your plug will have little specks of what appear to be aluminum or metal. They will be metalic in color. This will indicate detonation.

The valve stem seals are easy to replace. It can be done without removing the heads. You could do it in a weekend, but you'll need some equipment. If it's too much trouble in acquiring the equipment and a knowledgeable friend, you can take it to a shop.

 

By "equipment" I'm assuming you mean a valve spring compression tool and a compressor. I have the compressor, so I guess I could do the leak down test myself, and will likely buy a valve spring tool at some point, since I will eventually do a cam/spring upgrade...AFTER I get my engine a bit more bulletproofed. Doing a cam/spring swap with existing oil problems would probably not be the best idea.

I may do a little poking around this weekend. If I find anything, I'll post it up.


-Mike

 

Yes, you've got it. Here's a place that has the tools you'll need.
http://www.powerandperformancenews.c...?Store_Code=PH