disappearing coolant

[malibujeff]

I have a 2000 Suburban with the 5.3L engine. It has 88k miles on it. Recently the coolant light came on. Looked at the tank and it was down about an inch. I filled it back up and a week later it was down again. The cycle continues...

There is no coolant on the ground and I cannot find a leak anywhere on the 5.3L engine. It looks like there might be some coolant in the oil. The engine still runs great.

I have read through the forums but they leave me a little confused. I have read some threads that say it is the intake and others that say it's not the intake on the 5.3L.

Is this problem the intake or the head gaskets? or something else?

Thanks,

Jeff

[Tuffdrvr88]

Im not sure if this is the right year, but check to see if you have any coolant in the back passenger side of the engine. GM did use a STUPID hard plastic line to flow coolan through the Intake Manifold for a while and that junk cracked so easy its ridiculous, give it a peak.

[MT-2500]

Originally Posted by malibujeff

I have a 2000 Suburban with the 5.3L engine. It has 88k miles on it. Recently the coolant light came on. Looked at the tank and it was down about an inch. I filled it back up and a week later it was down again. The cycle continues...

There is no coolant on the ground and I cannot find a leak anywhere on the 5.3L engine. It looks like there might be some coolant in the oil. The engine still runs great.

I have read through the forums but they leave me a little confused. I have read some threads that say it is the intake and others that say it's not the intake on the 5.3L.

Is this problem the intake or the head gaskets? or something else?

Thanks,

Jeff

Could go either way but if there is coolant in the oil get it checked out and fixed fast.
A block chemical check test and a coolant pressure test and good inspection by a good repair shop may narrow it down.
MT

[malibujeff]

Originally Posted by MT-2500

Could go either way but if there is coolant in the oil get it checked out and fixed fast.
A block chemical check test and a coolant pressure test and good inspection by a good repair shop may narrow it down.
MT

I did the coolant pressure test last night and could not find a leak anywhere. What is a block chemical check test? What do I need to do this?

[Elbert]

Originally Posted by malibujeff

I have a 2000 Suburban with the 5.3L engine. It has 88k miles on it. Recently the coolant light came on. Looked at the tank and it was down about an inch. I filled it back up and a week later it was down again. The cycle continues...

There is no coolant on the ground and I cannot find a leak anywhere on the 5.3L engine. It looks like there might be some coolant in the oil. The engine still runs great.

I have read through the forums but they leave me a little confused. I have read some threads that say it is the intake and others that say it's not the intake on the 5.3L.

Is this problem the intake or the head gaskets? or something else?

Thanks,

Jeff

carry it in and get it checked out. Coolant in the oil is bad news... leaking head gasket, leaking intake gasket??? You are in real danger of bearing damage. Get the oil and filter changed ASAP and don't drive it. ITs not going to be a good day if a rod or main bearing goes out.

[MT-2500]

Originally Posted by malibujeff

I did the coolant pressure test last night and could not find a leak anywhere. What is a block chemical check test? What do I need to do this?

A block ckecker chemical test is a tester that checks for head gasket/exhuast gas leakage into the coolant system. It is a round tube with chemical in it that will change color if any exhuast gas in the coolant system.
Or in other words it will tell you if it is a bad head gasket or cracked bloc.
Here is one under combustion checker.
http://tools.batauto.com/index.php?c...mode=cat_click
Also there is a dye test kit . You can put dye in coolant and put a special black light on it and see where it is leaking.
Did you leave the pressure tester on it very long and check for a leak down on tester.
And always ckeck cold and the check warm and then check hot when doing either test..
It the block check tester does not show head gasket leak and you do not have any external leaks anyplace and coolant in oil you need to check or replace the intake manifold gaskets.
Good luck and let us know how it goes.
MT

[Ingoldx1]

Do the pressure test agian. When you are done pull the plugs and if it is leaking into the cylinders you will see anit-freeze on the plugs. I had two cracked heads and that is how I found out.
- Ingoldx1

[yukonator]

I have the same problem in my 2000 yukon xl 5.3 currently 110k miles.
I've taken it to the dealer multiple times and they cannot figure it out.
They did the dye test and the pressure test.
Its been going on for about a year now.
Also just experienced a sudden drop oil pressure from about 40 to about 20.
I'm thinking I've got a leaking gasket somewhere.

[MT-2500]

Originally Posted by yukonator

I have the same problem in my 2000 yukon xl 5.3 currently 110k miles.
I've taken it to the dealer multiple times and they cannot figure it out.
They did the dye test and the pressure test.
Its been going on for about a year now.
Also just experienced a sudden drop oil pressure from about 40 to about 20.
I'm thinking I've got a leaking gasket somewhere.

Welcome to your first post on AF.
Man it sounds like you may have major problems and had better get it fixed fast.
It would be a good idea to start a new post on your problem.
If they done the dye test and done it right something should have showed up.
Take a check on the engine oil.
Is it still good and clean. Put the dye check light on a sample of the oil.
If they have dye in the coolant and any is getting in the oil it will show up under the light.
If you are losing oil pressure do not fool around get it fixed even if you have to find another repair shop.
MT

[yukonator]

The oil pressure is actually stable at about 25 when at idle and about 40 when driving. It used to be about 35 and 45 before the sudden drop. The dealer said that it could be the use of the lower weight oil I put in last time I changed the oil. I'll change it this weekend to a higher wieght and see what happens.

As for the coolant, you would think the dealer would run the dye & pressure test properly. They say it all checks out fine. I say, so where's my coolant going?
I am looking for another shop but haven't found any highly recommended ones yet.
Thanks for your input

[MT-2500]

Originally Posted by yukonator

The oil pressure is actually stable at about 25 when at idle and about 40 when driving. It used to be about 35 and 45 before the sudden drop. The dealer said that it could be the use of the lower weight oil I put in last time I changed the oil. I'll change it this weekend to a higher wieght and see what happens.

As for the coolant, you would think the dealer would run the dye & pressure test properly. They say it all checks out fine. I say, so where's my coolant going?
I am looking for another shop but haven't found any highly recommended ones yet.
Thanks for your input

Different weight oil should not affect the oil pressure after warm up.
Oil pressure is controlled by the oil pump bypass valve.
But do not depend on the electric gauge to be right.
Are you using a good ac-delco filter?
If it is losing coolant you need to find out where it is going.



Check around Ask around
Word of mouth.
Family friends coworkers neighbors business people and delivery people.
Mailmen and parcel delivery people get around and notice a lot of stuff.
Even a good parts house knows what shops are good and not good.
Chamber of commerce and better business bureau and city hall.
If you find a good referral to a repair shop go look them over and talk to them.
Look for a clean looking busy place with nice people running it.
Ask a few questions and ask about their qualifications and training.
Not all places have trained tech/mechanics.
If they do not find a place that does.
Even all dealers do not have all trained techs/mechanics.

Also a tip on going to dealer.
Tip on going to the dealer
Ask that only a factory certified gasoline engine performance specialist work on your car.
Not all dealerships are concerned with how repairs are dispatched, and not all dealership techs bother to take advantage of the training offered by Ford (the vast majority of which is paid training). If the dealer is uncooperative, ask for your money back and call around for a dealer that will accommodate you.


MT

[yukonator]

Thanks MT.
I took your advice and went and had a talk with the service manager at the dealer. Told him I want the "good" mechanic and that I was loosing confidence in them. They did the die test again and this time took off the valve cover and reported a cracked head.
Kind of a bummer to have a cracked head ( if it really is cracked), but at least I wont' waste time only changing gaskets now that I know the real problem.

[MT-2500]

Originally Posted by yukonator

Thanks MT.
I took your advice and went and had a talk with the service manager at the dealer. Told him I want the "good" mechanic and that I was loosing confidence in them. They did the die test again and this time took off the valve cover and reported a cracked head.
Kind of a bummer to have a cracked head ( if it really is cracked), but at least I wont' waste time only changing gaskets now that I know the real problem.

Well it sounds like they are making progress on it. I am not sure how they can tell a cracked head from a head gasket. But it sounds like the heads need to come off and be checked by a machine shop. And go from there.
Good luck and let us know how it goes.
MT

[atvfanatic]

Had the same problem on my 01 Silverado (disappearing coolant), turned out to be the head gasket as well.