Over heating again/still

Tiny
TIM DONOHUE
  • MEMBER
  • 2003 CHEVROLET VENTURE
  • 1.4L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 70,000 MILES
Hello again,

Initially, we were told that there was an issue with the 3.4L overheating due to the failure of the intake manifold gaskets, so we replaced them. After a short while, the problem returned whereby all the coolant was going into the reservoir. We were then told that there was exhaust leaking into the cooling system and that we had a blown head gasket. We replaced the head gaskets and reassembled the engine again with all new gaskets and bolts properly torqued.

The engine was purring and running great for about a month until yesterday whereby it began overheating again. The gauge had been holding steady at 3/8 and would occasionally go up to 1/2 but quickly return to 3/8. The heat was coming on right away with no issues. During this time the only thing I keep adding was transmission fluid. I had removed the radiator to clean out the brown sludge which I have been told was a by-product of the original Dex-Col. I've been running it with plain water to flush out the remainder of the sludge and check for leaks before adding the new antifreeze.

Yesterday however when it went over 1/2 to about 5 to 6/8 I stopped it only to find out the coolant reservoir was now full with brown sludge on top and when I opened the bleeder valves they were slowly emitting the sludge as well. When I opened the radiator cap, after it had cooled, the fluid began returning to the radiator.

The fans are working like they should. It was mentioned that it might possibly be a defective radiator cap which I replaced but to no avail.


What would cause the coolant to go into the reservoir?
Is it possible I lost another head gasket after only a month?
Could I have ruptured the trans coolant tank within the radiator?

I am totally perplexed any help would be greatly appreciated.
Thanks,
Tim
Sunday, November 3rd, 2019 AT 6:12 AM

9 Replies

Tiny
ASEMASTER6371
  • MECHANIC
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Good morning,

Did you have the cylinder heads checked for being warped? That is required.

Did you replace the head bolts? You cannot reuse those bolts. If you did, that may be the issue.

Roy
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Sunday, November 3rd, 2019 AT 7:42 AM
Tiny
TIM DONOHUE
  • MEMBER
  • 19 POSTS
Thanks for getting back so soon.

Yes and yes. They were checked and planed and we used all new bolts for the heads and the manifold. They were all torqued to specifications.
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Sunday, November 3rd, 2019 AT 8:05 AM
Tiny
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Is there still any sludge in the system?

I think you need to have a leak test done again to see if you have a head gasket leaking.

Roy
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Sunday, November 3rd, 2019 AT 8:19 AM
Tiny
TIM DONOHUE
  • MEMBER
  • 19 POSTS
Yes, there's still sludge in the cooling system and I'm trying to flush it out before adding the antifreeze. Unfortunately, there aren't any radiator shops around here and I removed it to flush it out myself but couldn't physically remove the sludge out of the block.
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Sunday, November 3rd, 2019 AT 8:30 AM
Tiny
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The system needs to be acid flushed with pressurized cleaning fluid to get the sludge out of the block.

Water flushing will not do it at all. It sounds like all that stuff is block sealer from the past.

Roy
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Sunday, November 3rd, 2019 AT 8:34 AM
Tiny
TIM DONOHUE
  • MEMBER
  • 19 POSTS
I happened to be the original owner and never used any block sealer nor, given the low mileage, has the cooling system been serviced. Do you think an acid flush will/might solve the problem?
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Sunday, November 3rd, 2019 AT 8:58 AM
Tiny
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It will get rid of the sludge in the block. The radiator would have to be power flushed as well.

Once you get the system clean, then you will need to see if the issue still exists.

Roy
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Sunday, November 3rd, 2019 AT 9:05 AM
Tiny
TIM DONOHUE
  • MEMBER
  • 19 POSTS
It looks like my nightmare continues. I'll give it a try, thanks.
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Monday, November 4th, 2019 AT 6:44 AM
Tiny
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You are welcome.

Keep me updated.

Roy
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Monday, November 4th, 2019 AT 8:05 AM

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