On a 2006 Yukon with 5.3 engine, I've been losing about half gallon of coolant every couple weeks. The oil in the crankcase gets dirty and the pressure goes down to about 30. If I change the oil, the pressure goes back to normal for about another 1500 miles. My thought was a bad head gasket. Any thoughts? What is the going price to swap out head gaskets?
Coolant Loss
- Thread starter Bob Miske
- Start date
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Welcome to the forum from Oregon.
Does sound like you could have a head gasket problem. Are you seeing any coolant on the ground? Have you pressure tested the system?
The coolant loss, into the oil, can dilute and contaminate the oil causing oil pressure loss.
The "going price" is subjective. Depends on the quality of the parts you choose to use and the labor rate at a quality shop that you use.
You are talking about a head gasket set, new head bolt kit, machine shop work to surface the heads and while off a valve job with new seals is warranted, oil, filter, coolant, replacement of anything found to be needed during disassembly.....etc. Plus all the labor. You may have oxygen sensor problems after all this work as well.
While you are at it, does it need belts, hoses, thermostat....etc?
We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.
If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.
Does sound like you could have a head gasket problem. Are you seeing any coolant on the ground? Have you pressure tested the system?
The coolant loss, into the oil, can dilute and contaminate the oil causing oil pressure loss.
The "going price" is subjective. Depends on the quality of the parts you choose to use and the labor rate at a quality shop that you use.
You are talking about a head gasket set, new head bolt kit, machine shop work to surface the heads and while off a valve job with new seals is warranted, oil, filter, coolant, replacement of anything found to be needed during disassembly.....etc. Plus all the labor. You may have oxygen sensor problems after all this work as well.
While you are at it, does it need belts, hoses, thermostat....etc?
We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.
If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.
To add to what @PNW VietVet listed, one or both of the heads could be cracked, and you could be looking at replacing those. There are a few posts about checking for cracked heads by removing the valve covers and inspecting. Most common heads to crack are Castech, but I don't recall the number on the casting. It'll be in the other posts.
Cracked heads are more common than head gaskets, unfortunately. Take a look at post 31 especially:
https://www.tahoeyukonforum.com/threads/latest-oil-change-oil-filters.99646/
https://www.tahoeyukonforum.com/threads/latest-oil-change-oil-filters.99646/
iamdub
Full Access Member
^^^ Yup to all. It sounds like it's still very fixable if you could stop driving it and do so. Otherwise, you're spinning it's death clock faster.
Pop off the rocker covers and look for coolant puddled around the bolt head(s) or evidence that coolant was there.
To give you an idea:
Pop off the rocker covers and look for coolant puddled around the bolt head(s) or evidence that coolant was there.
To give you an idea:
Joseph Garcia
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Welcome to the Forum from NH.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. You have already received some initial feedback, and other folks will chime in with their suggestions.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. You have already received some initial feedback, and other folks will chime in with their suggestions.
Oh yeah, I didn't notice this was your first post Bob. Welcome!
Too bad it's about losing coolant though. If it is a cracked head I hope you have caught it early enough to save the engine. I didn't believe it before, but sludging oil is a sign of coolant mixing with the oil, which is often related to a cracked head.
BTW, it took me about 1/2 hour to pop both valve covers off. I pressurized the cooling system so I could prove to myself that water was indeed seeping from the crack.
I spent about $2000 Cdn on mine, but I had a local machine shop rebuild both heads completely, and I installed new lifters, rods, and rockers.
Too bad it's about losing coolant though. If it is a cracked head I hope you have caught it early enough to save the engine. I didn't believe it before, but sludging oil is a sign of coolant mixing with the oil, which is often related to a cracked head.
BTW, it took me about 1/2 hour to pop both valve covers off. I pressurized the cooling system so I could prove to myself that water was indeed seeping from the crack.
I spent about $2000 Cdn on mine, but I had a local machine shop rebuild both heads completely, and I installed new lifters, rods, and rockers.
