Coolant loss with no external leak

[Sepiroth]

It's a good thing the posts weren't really dealing any longer with intakes then.

The posts shifted to talk of head and head gasket failures.

 

[Baraney]

I have a 2002 1500 Silverado the V8 5.3 with 75k. It is leaking coolant into the oil. At this time they are pulling the heads to see if they are cracked. They told me I may have to replace the Engine. I think the sucks only 75k out of an engine how will Chevy stay in business building trucks like this.

 

[shadow]

I have a 2002 1500 Silverado the V8 5.3 with 75k. It is leaking coolant into the oil. At this time they are pulling the heads to see if they are cracked. They told me I may have to replace the Engine. I think the sucks only 75k out of an engine how will Chevy stay in business building trucks like this.

Jeez, that sucks. Might only be a head gasket though, which would cause the same symtoms. If you did not run your engine too long with that problem, the engine should still be OK. If you haven't gone back to the dealer to get the work done yet, you may want to try the Barrs stop leak or sealing tabs from GM. Maybe retorque the heads also might help, not sure, but if those steps work, might save you a bundle. Good Luck with it....

 

[BLACK_DENALI]

Subject:Information on Gradual Coolant Loss Over Time with No Evidence of Leak Found #06-06-01-019B - (06/12/2007)



Models:2004-2006 Buick Rainier
2001-2006 Cadillac Escalade Models
2001-2006 Chevrolet Avalanche, Blazer, Silverado, Suburban, Tahoe, TrailBlazer Models
2001-2006 GMC Envoy, Jimmy, Sierra, Yukon Models
2001-2004 Oldsmobile Bravada
2005-2006 Saab 9-7X
with 4.8L or 5.3L VORTEC® GEN III, GEN IV V8 Engine (VINs V, T, M, B, Z -- RPOs LR4, LM7, LH6, L33, L59)


This bulletin is being revised to include engine RPO L59. Please discard Corporate Bulletin Number 06-06-01-019A (Section 06 - Engine/Propulsion System).

Some vehicles may experience a gradual coolant loss over time. A very low percentage of cylinder head(s):rolleyes2: manufactured with an embossed Castech logo may develop a porosity crack in a very specific area.

Inspect the cylinder head assembly to determine if the casting was manufactured by Castech. This can be accomplished by inspecting for their casting logo located on top of the intake port, under the rocker arm support rail and in the spring deck cavity portion of the cylinder head.

Important: If the cylinder head(s) are Not a Castech casting, follow normal diagnostic procedures in SI to determine the cause of the coolant loss.


If the cylinder head(s) is a Castech casting (1), inspect the area around the five oil drain holes for witness marks indicating coolant seepage over time (2).

Important: If No evidence of coolant loss is found on inspection of Castech casting cylinder head(s), follow normal diagnostic procedures in SI to determine the cause of the coolant loss.



The crack location can be found in any of the five cylinder head(s) oil drains. This can be seen as a clean or shiny area, on an otherwise stained surface (1). Pressurizing the cooling system at this time may reveal coolant, air, or a combination, weeping in the described area. If inspection reveals evidence of coolant witness marks (1), replace the entire cylinder head(s) assembly.


© Copyright General Motors Corporation. All Rights Reserved.

Document ID# 1986750

I see, possibly a massive recall or class action lawsuit in GM’s future!

 

[ghostface]

that makes me wonder now cause sometimes when im driving i can smell antifreeze as if it s burning off, but my reservoir has never been low enough to set off the light. just another thing im going to have to look at

 

[DBPLAYA00]

BLACK_DENALI is right, kinda sucks cus it means new heads instead of just new gaskets.

 

[2001Yuke]

Subject:Information on Gradual Coolant Loss Over Time with No Evidence of Leak Found #06-06-01-019B - (06/12/2007)



Models:2004-2006 Buick Rainier
2001-2006 Cadillac Escalade Models
2001-2006 Chevrolet Avalanche, Blazer, Silverado, Suburban, Tahoe, TrailBlazer Models
2001-2006 GMC Envoy, Jimmy, Sierra, Yukon Models
2001-2004 Oldsmobile Bravada
2005-2006 Saab 9-7X
with 4.8L or 5.3L VORTEC® GEN III, GEN IV V8 Engine (VINs V, T, M, B, Z -- RPOs LR4, LM7, LH6, L33, L59)


This bulletin is being revised to include engine RPO L59. Please discard Corporate Bulletin Number 06-06-01-019A (Section 06 - Engine/Propulsion System).

Some vehicles may experience a gradual coolant loss over time. A very low percentage of cylinder head(s):rolleyes2: manufactured with an embossed Castech logo may develop a porosity crack in a very specific area.

Inspect the cylinder head assembly to determine if the casting was manufactured by Castech. This can be accomplished by inspecting for their casting logo located on top of the intake port, under the rocker arm support rail and in the spring deck cavity portion of the cylinder head.

Important: If the cylinder head(s) are Not a Castech casting, follow normal diagnostic procedures in SI to determine the cause of the coolant loss.


If the cylinder head(s) is a Castech casting (1), inspect the area around the five oil drain holes for witness marks indicating coolant seepage over time (2).

Important: If No evidence of coolant loss is found on inspection of Castech casting cylinder head(s), follow normal diagnostic procedures in SI to determine the cause of the coolant loss.



The crack location can be found in any of the five cylinder head(s) oil drains. This can be seen as a clean or shiny area, on an otherwise stained surface (1). Pressurizing the cooling system at this time may reveal coolant, air, or a combination, weeping in the described area. If inspection reveals evidence of coolant witness marks (1), replace the entire cylinder head(s) assembly.


© Copyright General Motors Corporation. All Rights Reserved.

Document ID# 1986750

I see, possibly a massive recall or class action lawsuit in GM’s future!

There seems to be quite a few "service bulletins" regarding these engines and transmissions. Why no recalls? New engine for Baraney and a new transmission for me, both at 75k

 

[leatherneck]

intake

P.S. not trying to call anyone out, but these vehicles have "dry" intakes, not "wet" intakes like back in the good oil "R" motor days, so, leaking intake gaskets would NOT cause any coolant in the oil or any coolant loss at all, but rather a lean condition and usually sets off the SES light when cold startup

This man makes sense obviously if you ever changed out a intake in a cast iron block the intake has the water neck on it vise on these iron blocks or LS blocks the intake is just that air intake your in and out water outlet for circulation through the radiator is from the bottom neck of the water pump to the upper neck of the water pump so i dont see how the intake would ahve something to do with it. I just recently did a swap in my 97 tahoe that now has a 04 5.3 tahoe engine in it and I'm noticing more than usual water coming out the tail pipe so obviously its either a warp head crack or bad gasket. which ever it is its not that bad cause the engine runs fine i do not lose much antifreeze at all but my temp does fluctuate from 160-210 so i believe it may be a combo of things water into the cylinders pump going bad

 

[stbeverlin]

I have a 2000 Tahoe with the same problem of a slow coolant leak. It turned out to be a bad water pump that only leaked when the engine was at normal operating temperatures. The only way to see it was to put it on a hydraulic lift and view it from below after I let the engine warm up enough to open the thermostat. I never had a drip shown on the driveway when parked which kind of threw me off. I had already replaced the water pump about 10000 miles ago and it went out again. I used a genuine AC Delco branded pump. I'm starting to question the quality of GM parts but maybe just a coincidence of two pumps going out that quick.

 

[leatherneck]

Well i did some looking around a lil more and found it was leaking out from the rear driverside head so i went ahead and took em off and had em checked cause i know i did run the engine hot once . So i had them pressure checked and they turned out good and the machinist just took off like.005 of an inch i put it all back together now and everything is running like it should i don't see any leaks nor do i smell antifreeze. Now i got to move on to the next project intalling the A/C brakcet and comp with lines. I was told since the heads are aluminum that they are more likely expand and contract under a lot of heat but at the same time it can also cause them to squish the head gaskets with it as well and when they contract at normal temp the gasket of course stays the same so i can sort of see why a head gasket leak can happen of course when they put it like that. on the other hand the heads are less likely to crack like iron heads would.. on this engine the truck can get up to about 210 before it kicks down in temp I'm not used to those temps on a engine but i hear thats normal for these 5.3's

 

[Va Tahoe]

possible solution

Has anyone experienced coolant loss without external leaks? We have a 2001 Tahoe with a Vortec 5300 engine. We have 85,000 miles.

I have the same problem that I have been dealing with for about a year now. I have problem solved with the gaskets and system pressure test and all were holding pressure fine. Took it to the dealership and and they informed me that they have found that there could be a defect in the cylinder head, A little crack in around the clylinder head. That reapair is very expensive sbout 2,500.00.........

 

[stbeverlin]

coolant loss without apparant leaks

I performed my 25K complete coolant change by a dealer who used the BG process. This uses a chemical flush, followed by new coolant, and an additive which prevents corrosion. It also includes a can of sealant. After this flush I have had no further coolant loss, so assume the sealant did the trick. This process was about 4K miles ago, and so far so good.

 

[arod]

these motors r notorious for this ...pop valve cover off and if u see a mess ...possible crack in head or blok...i went thru it...