hlatigo

Hi EVeryone

Out of poverty I had to slowly learn how to work on my car. Two weekends ago, I Ventured off to do two projects that I have never done, Change the oil pan gasket and the intake manifold gasket. To my surprise they weren't all that hard to do and surely don't warrant the 1,200 dollars that Chevorlet wanted to fix the car for me.

Everything went well and I had no extra parts

BUT...Two things, I have just read there is a sequence to how I am suppose to tighten the manifold back, which I didnt do. Does anyone know if this really makes a difference and if it does what would it do and should I Take the manifold off again and redo it with new gaskets?

My next problem is, I have low oil pressure. Although I have a 95 LT1 with 160,000 miles on it, I have never had any problems with low oil pressure throughout all the years. Does anyone know what I could have done wrong?

I made sure not to drop any junk from the manifold into the engine and other than that, I am not sure what I could have done other than maybe break the pressure gauge which I dont know where it is at. Your help is truly appreciated since I would like to fix this issue this weekend.

Thanks!

HL

Unriced

How is the oil pressure acting?
Is it low going around a corner, coming to a stop,
or taking off ? Maybe you bumped the pick up.

You might not have put enough oil in after the fix.
You lose alot of oil when you drop the pan..

JAKE

There is a recommended torque sequence for the intake manifold and it differs from the conventional - start in the center and work toward the ends alternating. I was surprised by the different sequence too when I first looked it up in the Shop Manual.

But since yours is installed, I don't believe you'll gain anything by removing and re-installing the intake. If you don't have any leaks, you lucked out.

I suggest you go over the bolts several times as the engine goes through heating and cooling cycles. The gaskets often compress, which causes the torque on the bolts to lessen. So they need re-torqueing a few times until the torque setting holds.

As far as the low oil situation, how low is low? What pressures are you seeing?

I'd first check the oil level with the dip stick just to be sure the proper amount is there. If that's okay, I'd next attach a pressure gauge to get a second opinion.

If it's still showing lower than normal/safe and you're using the same weight oil, I can't help but think it was something you did when the pan gasket was being changed.

If the pickup isn't welded to the pump and you tweaked it while installing the pan, the pickup could be sucking air.

If the pressure readings are in the danger zone, less than 10 psi at idle, I wouldn't run the engine until the cause is corrected. So if less than 10 psi with the correct amount of oil in the pan, I'd jump right to dropping the pan again rather than idle the engine with less than a safe amount of pressure.

If you have 6 or 8 psi, you MAY get by, but I wouldn't chance it.

Keep us posted on what you find.

Jake

hlatigo

Thanks for the response.

Hmmm...where do I begin.

At first i was getting very low pressure around 10psi (in the danger zone) but as i speed up to about 70mph it goes out of the danger zone but only a little pass the first click.

Most recently, when I turn on the car is is halfway in between the first and second click and it will stay there for awhile but than in about 30 minutes if I am in idle it goes into the danger zone. But if be driven it will stay right outside of danger zone but back in when I stop and in idle.

Never checked what it does around a curve and I have been very careful with driving it but it is the only car i have. I was planning to take the pan out again and checked to see if there is anything in their that could be blocking the flow but don't really know where to check if I do. Since I had to take the filter off, I planned to check that again too. I placed 6 quarts of oil in when I replace the oil pan gasket and i checked to see what it had almost everyday. It isn't dropping and it had a little more than what it should have but not too much (i dont think).

So any ideas where I should start this weekend? I am hoping to GOd that it isn't the bearings because I keep reading that maybe a cause.

Thanks!
Latigo

JAKE

Since the oil level in the pan is okay, (and I'm assuming you're using the same weight oil) I'd head to the auto parts store and pick up a mechanical oil pressure gauge to see the exact oil pressure psi in numbers.

On the 86, you just unscrew the sending unit from the back of the block next to the distributor and screw in the new gauge. Then fired it up and check the pressures with the engine cold and hot.

This will tell you if you REALLY have a problem or if it's the sending unit itself that needs replacing.

Depending on what the new gauge shows, you may or may not have to drop the pan.

Keep us posted.

Jake

hlatigo

Ok sounds great I will do that. I have read that on my internet search of oil pressure.

Given the pressure and the fact that I dont drive longer than 30 minutes at a time, is it ok for me to still be running the car. I dont have much of a choice, but want to take advantage of Chevrolet being open in case I need to buy any specific parts.

Can you think of any little gauges that maybe in need of replacement that isn't too expensive that I can go ahead and do to make sure it isn't one of those?

Latigo

MikeC4

FWIW, my '95 gives me readings very similar to yours. My oil pressure is reasonably high before the engine gets hot (my assumption here is that the oil is thicker when it is at lower temp). After driving for awhile, my oil pressure drops to around 10psi when I am idleing(my assumption here is that the oil is thinner at high temp, and thus harder for the oil pump to maintain higher pressure). Sometimes my 'check gauges" light flickers when I am at stop light and idling. Upon acceleration , the pressure rises as expected and the flickering light goes off. Maybe I should be concerned about this, but for some reason, I am not. I run castrol 10W/30 in my LT1. My philosophy on oil pressure is:

any pressure at or above 10psi is safe.....

hlatigo

hahaha...i like your philosophy and my light has yet to flicker on but I have read that most warnings lights do not turn on until the pressure hits about 6psi or less. Nevertheless, i have been driving the car for 11 years now and I am pretty sure it has never been this low before.

Its somewhat comforting that yours continues to run without a problem but I don't want to take any chances since I use this car everyday.

I read something about varnish buildup and/or sludge...anyone know where this would buildup and so I can go ahead and clean it for safety purposes.

Latigo

JAKE

The last one I bought was from ACE Hardware It had a zero to 60 psi scale and I used it when priming a newly built engine.

I took the sending unit with me to make sure I bought the correct diameter and thread male adapter so it would screw into the block.

I teflon taped the threads (LEAVING THE FIRST TWO OR THREE THREADS CLEAR) to prevent any leakage.

The whole she-bang was less than $10

Jake

hlatigo

Ok...thanks for everyone input. B4 i even knew if this is what the problem was, I bought a oil pumping pressure unit. When I went to install it, sure enough the old one was cracked. I assumed i cracked it when I chnaged the manifold gasket. The second I turned on the car, the pressure was back to normal and all worries gone. Which I am very grateful for.

HOWEVER!! feeling a little mighty by my accomplishment, i decided to change the manifold / header gasket. I was surprisenly able to get to all the bolts but when putting them back. I could not get the formost front bolt in and one in the middle was stripped (not the bolt, but the acutal chamber). Should I glue or do anything else to make sure the headers do not leak? I don't think it is cost effective to switch out a whole new manifold for just one stripped chamber. Any ideas anyone?

Latigo

JAKE

Glad to see you found the cause of your problem.

Was it the oil pressure sending unit that was cracked? The little "light bulb" looking arrangement mounted near the distributor. If it is can you send me the part number. I wanted to replace mine but the parts store couldn't find it. I removed the one on my car and there's no part number on it, only the number "80".

If by "chamber" you're referring to the hole in the cylinder head you have a couple of options.

First you can use a thread chaser, to clean and straighten the threads. Just take one of your existing bolts with you so you can get the correct size thread chaser. They're available at most auto parts stores and many of the largers hardware stores, too, like ACE. It should be 3/8" coarse, but GM uses metric threads/bolts in different places it's best just to take one of the bolts with you.

The other option is to install a heli-coil in the head. A heli-coil is a little insert (looks like a short, small spring) that once installed creates new threads for the bolt. There are inexpensive kits that come in different sizes. The kit includes a tap used to cut new threads in the hole for the insert to screw into; the inserts and a little plastic installation tool.

A heli-coil will be difficult to install in the exhaust with the head installed on the engine.

I'd try chasing the threads first, since it's the easiest to do and may well solve your problem.

As far as the bolt that won't go in, it's probably because the hole in the exhaust (we are talking about the exhaust, right?) and the hole in the head aren't correctly aligned.

You should start each bolt by hand first before torquing any of them down. Sometimes torquing down the other bolts before starting them all will cause a misalignment and problems in starting the remaining bolts.

Check the bolt threads and the threads in the head bolt holes to make sure the threads aren't damaged. If they are damaged you can chase the head threads using the same thread chaser and use a die to straighten the bolt threads, or just buy another bolt.

When chasing the threads, insert the chaser, making sure it's straight, then turn it a couple of times to begin straightening the threads. Then back the chaser out, clean any filings off, then re-insert the chaser and turn it a couple of times to get you back to where you were. Now turn it a couple of more times, take it out, clean, etc. Keep doing it this way, a couple of additional turns at a time, until the threads are straight again.

One trick on installing a bolt straight is to turn it backwards very slowly, counter-clockwise, you should be able to feel it drop just a hair as you do. Once you feel it drop, begin turning it in the tightening - clockwise - direction.

Keep us posted.

Jake

hlatigo

HI Jake and everyone

First of all, the part number to the pressure sending unit is:

Part NO. 10201491 1800 96 @ sensor


That is what it says on my receipt, I hope this helps. I got it at the Chevorlet dealer for $48.62.

Yes it was the header I was trying to get back on and although i had them all lose, i just couldn't seem to get the first one (fron of engine) in. I will try to get it in later.

I will go look for the coil and try my luck in a couple of weeks. Thanks so much for your help.

Latigo