QuestionQUESTION: Hi Roland,
I have been puzzled by a 1999 Chrysler Voyager 3.0 V6 with an Auto. Trans., Air, P.S. and just had Head Gaskets replaced because of Overheating and pressure loss in coolant system. Heads were tested, new gaskets and Coolant. Ran in yard for 30 minutes with no problems. Fans cycled and drove around short distance. Yesterday the Van was driven for 25 to 30 minutes and overheated. Let cool some. Topped off coolant with my Rad. Funnel, and while running, it overheated and spewed Brown coolant up while boiling over. Seems to have bubbles while coolant circulates now. Never saw this before. Help!!
ANSWER: Hi Dale,
If you hear bubbling going on in the cooling system soon after starting the cold engine then there is still a leak between the cooling system and a one or more of the engine cylinders which is what puts air into the cooling system and that causes the bubbling. There is a test tool which can be put on the radiator fill opening which can detect the presence of exhaust gas coming from the radiator if this is the cause.
Brown coolant is also suspicious, perhaps it may be also oil in the coolant? What color was the fresh coolant when first put in?
How does the oil on the dipstick look? Is it at all cloudy, which would suggest also that there is a coolant leak between the oil system and the cooling system.
How about the radiator? Is it about equally hot comparing the temp of the two side tanks with your finger? If one side is much cooler than the cross channel tubing may be partially blocked with crud. Was the radiator flushed at all recently?
Other than the loss from boiling over, is there a sign of any other leakage of coolant?
I would return to the shop that did the gaskets and let them diagnose and repair the problem, at no cost to you given what you have already spent on this situation. They may have either not done the repair properly or misdiagnosed the problem and done the wrong repair to begin with.
Please 'rate/nominate' me/my answer (see the PS below).
Thanks,
Roland
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QUESTION: Roland, The coolant was new (1.5 gal.) Green, Oil clear before and still clear. I did the R&R myself and paid 90.00 to get the heads pressure tested. On the initial start up, I saw only normal coolant, nothing out of sorts wrong. I took out the Thermostat to rule it out, but no luck. The Radiator is 2 yrs. old, Motor was changed Feb. of last yr. Checked both hoses for collapse, both OK. I was draining the coolant out to try flushing when you responded. I will check for even on temp. of both sides of Radiator in a few minutes. I noticed some rust looking tint to the coolant I drained to get the flush and as much fresh water in it as possible. Will get back to you shortly on temp. difference. Motor doesn't misfire one bit. Thanks, Dale
ANSWER: Hi Dale,
Does the system begin to make bubbling sounds before it even heats up to operating temperature? That would be a sign of there still being a head gasket leak or possibly a crack in the block or one of the heads. Also note that the thermostat has to be rotated to the proper position when inserted into its housing in order to clear an internal flange.
I will be 'out for the next 5 hours but back again early evening/late afternoon.
Please rate my answer.
Roland
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QUESTION: Hi Roland, The tanks on the Radiator are heating roughly evenly. Today I see bubbles even before operating temperature achieved. I am using a fill funnel to monitor activity in the coolant while engine is running. I have held off re installing Thermostat until I was draining to put coolant back in. The bubbles are small and very few at idle, but rev the engine for 20 to 30 sec. and the amount is almost continuous. Does this sound like a crack in the block to you? I understand you will be out for 5 hours. Thanks for your insight, Dale
AnswerHi Dale,
It is unclear to me whether this is a leaking head gasket (between a cylinder and an adjacent coolant passageway or a crack in the block with a similar crossover between a cylinder wall and a coolant passageway. You might be able to at least localize it by checking the compression of the 6 cylinder to find which one is lower. You might also first want to check the torque on the cylinder head bolts in the hope that it is a gasket leak due to a slightly less than spec torque on one of them. The final torque is supposed to be to 80 foot-pounds.
If that doesn't correct it, then do check the compression, find the low cylinder, remove the head on that side and look carefully for evidence of a gasket leak, or cracks around that cylinder's head and cylinder wall. You might do well to go to a radiator shop and have them verify whether you have the presence of exhaust gas in the cooling system (the bubbles) which would definitely implicate some sort of leak as I have hypothesized.
Best of luck on this and please keep me informed of progress.
Please 'rate' my answer.
Thanks,
Roland
