GM Truck Club Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
Hello

A few days ago I purchased a 2004 Chevy Suburban, V8 - 5.3l and I was very happy with it until yesterday morning
When I started the engine everything looked ok and I went to work, but then when I got in the "stop and go"traffic the warning went of saying Öil Pressure low"
I saw that as soon I would accelerate the pressure went up again and after driving around 30min everything looked ok.
Same happend after work, car was cold and it took again a while before th pressure didn't dropped
It seems that this only happens when the car is cold and when the engine runs on low RPM (waiting on a traffic light etc) then after i accelerate the pressure goes up til 265 and when the engine is warm it goes up till 275 (middle of the clock).
Anyine here who has an idea what that could be?

I got the car from a dealer here in Costa Rica, so it does comes with warranty, but it looks like his mechanic has no idea what the problem could be. So I would like to put him in the right direction.

Thanks

Louis
 

·
Premium Member
Joined
·
6,542 Posts
Worst case scenario is the oil pump is going bad, seals leaking (internally into the oil pan) or just plain worn out.
I'm guessing your first check was to see the oil level is at the correct mark on the dip stick, and if you had any large external oil leaks.
You might try getting an oil change, make sure they use the manufactorors recommended grade of oil.
I've seen these engines run low oil pressure when the oil is due for a change or if the oil change was done with a lessor viscosity oil than called for.
 

·
Registered
Joined
·
561 Posts
i agree with above........change the oil and filter with the recomended oilmaybe get a good auto meter or VDO guage and verify the dash gage is correct.....most of the time it is senses 10+ presure and moves up but it really is a dummy light not guage........mike
 

·
Registered
Joined
·
7 Posts
Discussion Starter #4 (Edited)
thanks for the replies

When I got the car the dealer did a oilchange, but I believe that he put in cheap oil (thats what they usually do here) so I will have the oil and the filter changed tomorrow morning

I really hope that this is the solution. Somehow it does makes sens, since the stikker inside the window says that the dealer has put in 20 W 50 and I just checked the manual where it says to put only 5 W 30 in. It even says to not use 20 W 50

So maybe I'm lucky and can fix it by just changing oil

In case of changing the oil pump, is this a major thing to do? I mean workwise
 

·
Registered
Joined
·
225 Posts
IMO 20-50 is fine in CR, I been going down for quite a few years. In the tight traffic and high temperatures you have to run in, I feel it will be better protection then 5-30.
 

·
Registered
Joined
·
22 Posts
the 20-50 could easily be the problem! theres numerous places that explain oil viscosities! do a search and put 5-30 in. i'll bet it solves that problem because once your heavy oil warms up its fine.
 

·
Registered
Joined
·
225 Posts
the 20-50 could easily be the problem! theres numerous places that explain oil viscosities! do a search and put 5-30 in. i'll bet it solves that problem because once your heavy oil warms up its fine.
Curious did you read the initial post, the problem shows up when the engine gets hot not cold as you seem to be relating to. 5-30 down there is like running kerosene and may in fact bring an early death to the engine! There is one thing over looked the oil cooler which is part of the radiator and may sludged up from poor grades oil oil, if the 20-50 is thinning that bad there are other issues!
 

·
Registered
Joined
·
7 Posts
Discussion Starter #9
Curious did you read the initial post, the problem shows up when the engine gets hot not cold as you seem to be relating to. 5-30 down there is like running kerosene and may in fact bring an early death to the engine! There is one thing over looked the oil cooler which is part of the radiator and may sludged up from poor grades oil oil, if the 20-50 is thinning that bad there are other issues!
No, the problem is when the engine is cold, after driving around 20 - 30 min the pressure stays constant between 255 and 275
Sorry for my bad english and not making that clear at my first post.

Will change the oil today and keep your guys posted

Thanks a lot for all the help

PuraVida

Louis
 

·
Registered
Joined
·
7 Posts
Discussion Starter #10
Yesterday I have changed the oil to 10W 30 as it says in the manual, but today i had the same problem again, Accelerating shows up ok pressure but as soon I had to wait on a stoplight the pressure would go down to almost 0 and on top it would start making a very weird nice, like hitting iron
so i ended up to call a towtruck and pulled hoim to the shop. Let them figure out whats wrong with it, since I just bought him and it has 3 months warranty

However this is
something i rreally don't understand, cause this is only happen when the car is cold

what could it be?
 

·
Registered
Joined
·
225 Posts
I have seen this happen when the filter bypass valve had a sliver of junk under it, I still say at the operation temps you run in heavier oil is in order. I have over 6K in 383 stroker and would not even dream of running anything other then 20-50, but also I do not run Dino in my engines.

Phil
 

·
Registered
Joined
·
7 Posts
Discussion Starter #12
I'm on the end with this car

Hello again

I have no idea what else to do, since the problem continues

Here is what the Chevy Dealership did so far

changing the oil to a thicker viscosity (20 w 40)
changing the oilpump
checking the electronic

This all took them 6 weeks by now and still the oilpressure drops when the engine is cold (but keeps stable when it's warm!!!)
Now they are telling me that the engine is bad and that they have to open it and obviously they will not do that for free

So far this car has given me only a big headache and I really have no clou what could cause this trouble. Friends tell me that they don't believe that's the engine since the oilpressure would drop when the engine gets hot and not vice versa,

I feel completelly helpless and really would appreciate if someone can point me in the right direction to get this nightmare ended.

Thanks a lot

Louis
 

·
Registered
Joined
·
22 Posts
now is definitely the time to invest in an oil pressure gauge and pull the oil sending unit and hook it up there. oil pump is probably the likely culprit if your oil pressure is low from this test. with this new of a vehicle i cant really see it being your lower end bearings... but... spun mains will do exactly what youre talking about. and whomever called me out on the oil- needs to do what i said and research it. bottom line. 0 w 20 is fine in costa rica too- but dont call me out unless u do the suggested research!!!
 

·
Registered
Joined
·
7 Posts
Discussion Starter #14
the mechanic put a pressure gauge on it and it really went down when engine is cold. They also changed this bypass valve and now they are speech less. They say it can't be the bearings since it would show low pressure when the engine is hot. But in my case it's only when it's cold and as soon it gets warm and you hit the engine up to ;ike 3.000 rpm it just stays at a good pressure

Could it be that the tubes are just dirty?

I mean at the moment oilpressure drops and i hit the engine for a few moments it stays on good pressure.

This drives me really crazy, since nobody here has a clou whats going on. The car is in 2 different shops now for a total of 8 weeks :(
 

·
Premium Member
Joined
·
6,542 Posts
Sounds a lot like a bad oil pump.
If theres no major oil leaks in the system and the oil pump drive isnt slipping even with the thicker oil you should see steady stabile oil pressure readings within a few seconds after start-up.
A bad oil pump out of the box wouldnt be unheard of.
 

·
Registered
Joined
·
2 Posts
uh oh

That sounds like you need a new oil pump, can't say for certain. But that weird noising that resembles the explanation of rod knock, which is connecting rod knock, which means that motor is a gonner if its not fixed like... right now. If you changed the oil already and it keeps it up definitly go get it fixed or you're beat for around 2000 dollars.
 

·
Premium Member
Joined
·
1,341 Posts
It could be that the oil return passages are crudded up. When idling, there isn't enough pressure to let the oil drain back into the pan to be picked up by the sump. It could be a bad oil pump, if it has an off-board oil cooler or remote filter, that could also be plugged up.

My '93 suburban had that problem too. The pressure was fine when cold, but then dropped off at operating temps. Even at times when the pressure gauge read dead zero, the engine didn't make any noises that are generally associated with oil pressure problems. It could be the passage to the sending unit that is plugged, giving the gauge the impression that there is no pressure.

of course, mine had 320,000 miles on it too.
 

·
Registered
Joined
·
33 Posts
Yesterday I have changed the oil to 10W 30 as it says in the manual, but today i had the same problem again, Accelerating shows up ok pressure but as soon I had to wait on a stoplight the pressure would go down to almost 0 and on top it would start making a very weird nice, like hitting iron
so i ended up to call a towtruck and pulled hoim to the shop. Let them figure out whats wrong with it, since I just bought him and it has 3 months warranty

However this is
something i rreally don't understand, cause this is only happen when the car is cold

what could it be?
With my 86 Chevy my oil psi goes from 15 to 30 to 7 and so forth. I can go and move the wires and it would go back up. I'd check the sending units first. That would eliminate an easy fix before assuming the worse. My 94 Thunderbird would lose psi when it was hot and that was due to the wire gettn loose from bouncing around while driving.
 

·
Registered
Joined
·
5 Posts
Yesterday I have changed the oil to 10W 30 as it says in the manual, but today i had the same problem again, Accelerating shows up ok pressure but as soon I had to wait on a stoplight the pressure would go down to almost 0 and on top it would start making a very weird nice, like hitting iron
so i ended up to call a towtruck and pulled hoim to the shop. Let them figure out whats wrong with it, since I just bought him and it has 3 months warranty

However this is
something i rreally don't understand, cause this is only happen when the car is cold

what could it be?
Good afternoon I have the same problem with my 04 Chevy Suburban I'm wondering if anyone has figured out what the problem is I've had so much work done only thing left is replacing the motor????
[email protected]
 

·
Registered
Joined
·
13,880 Posts
I can only pass along my experience, I only use synthetic oil, however during one oil change, a real good filter wasn't used; and I got the low pressure message.

An oil change with a good synthetic filter fixed the problem.
 
1 - 20 of 22 Posts
Top