Leak coolant , head gasket ?

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My 2000 silverado z71 vortec 5.3L 186k have a small leak in back of the motor, found 1-2 drop of coolant stuck bottem of the oil pan. I lost coolant but not much, my coolant level alway stay at cold mark, when cold or hot it alway stay at cold mark, if I add more coolant, it will drop down to cold mark after drive for day or 2. My reservoir never ran dry.

This reason why I think head gasket

on the other thread where I ask about milky/steam water under the oil cap, since I drive very short trip 10min a day and if I wipe milky stuff off and I drive long trip and get on highway often no more milky stuff under oil cap, and I check back next day after yesterday long trip, no milky stuff. but still see steam water stuck under oil cap after long drive ( I dont know if my pcv system is working correctly, im using the new update pcv from dealer, where it does not have anything inside the pcv , it just have a very tiny hold at the bottem of pcv ( mabe I should try the old click type pcv ).

Thing I already check, oil on dipstick look brand new still golden color and in correct level. No smoke in back exhault and no sweat smell. no bubble inside the coolant reservoir , truck idle and run strong. Never over heat, the temp guage alway behind the middle mark, middle mark is 210, so I guest around 190-200.

I went to autozone to do the coolant pressure test, my coolant cap say 15 psi, I pump in 15 psi and it hold pressure. I saw the leak in back, but cant tell where its. Take to my mechanic and told him what going on, first thing he say is heater core slow leak. Then I pop the oil cap and he saw couple steam water stuck to it and steam water stuck on the fill neck he say it look normal, but not that much condention. Then He have to go, so I take the truck home and park. I dont plan to keep run the truck until I have enought moneys and time to ready fix what ever is wrong with it.

When im ready , im thinking take to dealer and let them check what going on. cause I dont have any shop in mind that I can trust. Any one know how much dealer charge to check for leak and tell me exactly going on ?

on the mean time, if you guy been in same situation or similar, can tell me what happent, if it head gasket, that is ok for me, I will fix it when I have moneys, mabe next month or so, I have plenty other car to drive. Im not worried or stress over it too much
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Originally Posted By: 229
Probably needs factory waterpump replacement.
ya I'm always doing a pump on one of those cause the wp gaskets are leaking. I have seen a couple. 5.3s that have external hg leaks though.
 
O/P said the back of the motor. Last I checked, the water pump isn't in the back...

It could be the head gasket(s) I suppose, but it could also be one of the coolant crossover passage plugs or a heater hose fitting leaking.

Could you tell us which side it's leaking coolant from?
 
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Originally Posted By: The_Eric
O/P said the back of the motor. Last I checked, the water pump isn't in the back...

It could be the head gasket(s) I suppose, but it could also be one of the coolant crossover passage plugs or a heater hose fitting leaking.

Could you tell us which side it's leaking coolant from?


The water pump is replace 20k miles ago. and coolant leak is on drive side, I havent seen it drip on the floor while running.

this picture is where I found 1-2 drop of coolant stick on it.



any one know how much dealer charge for checking for stuff like this ?
 
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we had a 1984 olds bought new. at 10,000 miles
small leak- 2 drops a night.
1. dealer changed head gasket- no change
2. dealer milled the head when changing head gasket again, no change
3. - dealer looked in tsb and found that the block had a porosity on many of those engine made within certain dates
4. dealer replaced the engine block, reusing all the cam and piston parts, new rings and bearings- took a week
 
It looks like you have little trails where the coating of brown goo that looks like burnt pork grease has been rinsed away. If you follow those trails upwards, where do they start?
 
carwreck, that link you provided made my computer play revving and shifting sounds at such low volume I thought the fan bearings on my CPU cooler finally bit the dust completely.
 
update : got a mechanic look over, he say the some small coolant line under the intake manifold is leaking, intake have to come off, job cost $350 dollar, wich is not bad, im scare is the head gasket
smile.gif
 
There you go then. $350 and your problem is solved. Taking care of little coolant leaks like that right away is a big part of how you get to keep your head gaskets intact for the life of the truck. One suggestion:

Considering the age of the vehicle it might be worthwhile to ask that all hoses (including PCV) to be removed during the repair be replaced with new OE hoses. There shouldn't be any additional labor charge to put a new hose on compared to putting the old one back on as it's actually less work with a new hose. It will save you from having to deal with them one by one over then next couple of years and your mechanic will get to order them all ahead of time so there's no running around trying to find a suitable part for any that crack as they're removed. For a few dollars more you both benefit.
 
Originally Posted By: yonyon
There you go then. $350 and your problem is solved. Taking care of little coolant leaks like that right away is a big part of how you get to keep your head gaskets intact for the life of the truck. One suggestion:

Considering the age of the vehicle it might be worthwhile to ask that all hoses (including PCV) to be removed during the repair be replaced with new OE hoses. There shouldn't be any additional labor charge to put a new hose on compared to putting the old one back on as it's actually less work with a new hose. It will save you from having to deal with them one by one over then next couple of years and your mechanic will get to order them all ahead of time so there's no running around trying to find a suitable part for any that crack as they're removed. For a few dollars more you both benefit.


10.gif
 
I can not picture what coolant hose the intake would have to be removed to replace. The metal line connecting the heads at the front should be pretty simple to replace. The rear should just have a block off plug on each side.
 
Originally Posted By: MetalSlug
update : got a mechanic look over, he say the some small coolant line under the intake manifold is leaking, intake have to come off, job cost $350 dollar, wich is not bad, im scare is the head gasket
smile.gif



The only thing under the intake is the knock sensors. I would get a second opinion.
 
Originally Posted By: AVB
I can not picture what coolant hose the intake would have to be removed to replace. The metal line connecting the heads at the front should be pretty simple to replace. The rear should just have a block off plug on each side.


sorry for late update. yub seem like no tube is go under the intake, and some how my coolant is stop leaking.
 
Are there two little rubber hoses at the bottom of the throttle body that could leak at the ends and drip and allow a bit of antifreeze to run under the intake to the back and finally down the back of the engine? If so, you should be able to see such hoses and any drips or lack of drips with a good flashlight and a small mirror-on-a-stick. The best time to check this would be during initial warm-up from full cold.
 
Originally Posted By: yonyon
Are there two little rubber hoses at the bottom of the throttle body that could leak at the ends and drip and allow a bit of antifreeze to run under the intake to the back and finally down the back of the engine? If so, you should be able to see such hoses and any drips or lack of drips with a good flashlight and a small mirror-on-a-stick. The best time to check this would be during initial warm-up from full cold.


Do you have any picture show the rubber hose you talking about ? My coolant suddently stop leaking I have no idea how.
 
I don't have any pictures. I'm not even sure you have them. It's just very common in GMs to have a pair of small rubber hoses carrying coolant attached to the underside of the throttle body. They keep it warm so it doesn't ice up while driving in cool weather.
 
I think it does have a heated throttle body, but my guess is one of the block off plugs bolted to the head are leaking probably the one on the driver's side. You will probably have to climb over the engine to see it. The plugs look like a little oval shaped aluminum block with 1 bolt in them, there is one in each head behind the intake manifold. They have a rubber coated metal gasket that seals them.
 
Originally Posted By: MetalSlug
update : got a mechanic look over, he say the some small coolant line under the intake manifold is leaking, intake have to come off, job cost $350 dollar, wich is not bad, im scare is the head gasket
smile.gif



Maybe he was talking about the coolant bypass hose or bypass cover. Look at 4 and 5 in the diagram. I'm not saying if it is leaking or not.

http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=371914
 
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