Replacing Head Gasket on High Mileage Motor

PhdNPrerunners

PhdNPrerunners

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Hey guys I am considering picking up another 4runner as a project and wanted to get some opinions on if I should replace the head gasket or try to find a low mileage used motor? The 4runner I am looking at has 316k miles and the current owner said that it has a head gasket leak but never over heats. I'm afraid it might be a waste of money just to replace the head gaskets on a such a high mileage motor. Do you guys think I should replace the head gaskets on the current engine? Thanks
 
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I've seen a few instances on the 5vz, where coolant leaks externally from the head gasket. It's not a terribly complicated repair, and would give you a great reason to replace the valve stem seals and make sure the valve clearances are still correct, any good machine shop can do it reasonably if you don't feel confident enough to do it yourself.
 
The OP is thinking about picking one up that he does not really know the history to either except that it has 316k miles. This means it was probably decently cared for to get that milage, but it is still nearing the end of its life. Totally depends on what your long term plans are. If your going to sell it just fix the head gasket as it will be less work and money. If you are going to keep it do a compression check and find out how good the rings and valves are. If I was going to keep it I would throw another engine in there, its more time and effort but a better chance of long term usage.
 
I'd rebuild, but know, you'll end up doing more than expected.

I have a rebuilder 3.4 if you're interested. Should be pulling it out soon to put the one I'm rebuilding in. Claimed to be 60K mile motor but i opened the VCs and it was full of sludge so i would definitely rebuild. Would just have to figure out a way to get it to the woodlands.
 
Joelzy said:
true, but if possible, pop the valve covers off and have a look before buying. the JDM replacement that was in my runner when i bought it had the worst sludge i've ever seen.
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Definitely. It's still a used engine.
 
Silver Supra said:
I'd repair your motor. When you buy a used one you have no idea what you're getting yourself into.
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The one he is currently buying has a known problem, and a fairly large job at that. He still gets to wrestle with the exhaust manifold.

I'd lean the other way and look for a used engine. An engine swap is easier than a head gasket.
 
Thanks for all the input guys! The guy I am purchasing it from has owned the 4runner most of it's life and he said he was keeping up with the maintenance on it. I find it a little weird that it doesn't overheat with a bad head gasket.

It does sound like replacing the engine is a better option than just fixing the head gaskets, especially since I plan on keeping it for a while and driving it a lot.
 
PhdNPrerunners said:
Thanks for all the input guys! The guy I am purchasing it from has owned the 4runner most of it's life and he said he was keeping up with the maintenance on it. I find it a little weird that it doesn't overheat with a bad head gasket.

It does sound like replacing the engine is a better option than just fixing the head gaskets, especially since I plan on keeping it for a while and driving it a lot.
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Everyone says they kept on maintenance if there's someone willing to buy. The guy I bought mine from said the same thing. Took a look at it and noticed the fluids were bad. When I got the oil changed guy said the oil in it was the blackest he had ever seen. Plus the transmission fluid was burnt, and the entire suspension was causing the tires to go bad.

You won't really know for sure all the things that are wrong until you own it.
 
Perhaps it needed the head gasket recall and it was never done? Mine leaked externally before I had it done at 120,000 miles. Now I did rebuild my heads after I managed to burn a valve at 360,000 mile mark. Best thing that ever happened. It runs like a new truck now. If the oil looks good, there is no sludge, and the compression check is fine I would have the head work done.

PS- If any of you guys have high miles and pinging issues. I highly recommend getting the carbon buildup cleaned out. Not talking Sea-Foam here. Has anyone tried walnut blasting? Seems way easier than pulling the heads.
 
We did a head gasket in a 4runner my brother picked up, although this was a clearly abused 4runner, it taught us a lesson. 70 miles after the head gasket was done the bottom end went. I'll never make that mistake again.

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I would at least pull the plugs on both banks and remove the valve cover on the passenger side to get a visual check on just how healthy this engine is.

If you have access to a leak down tester and a portable compressor, that would be even better.....
 
current owner said that it has a head gasket leak but never over heats
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If owner says it has a problem but the details are scare I wouldn't assume for sure that the issue is as simple as the head gaskets. It could be any number of things with those miles. Like LittleCaesar said a leak down test should give you a better idea. If you are like me and don't have access to one a shop should be able to do this fairly cheap.
 
Well, if he says it doesn't overheat then take it on the road and plug in a scanner. Also, regardless of what he said you may be dealing with a warped head.

Is it his daily driver?
 
PhdNPrerunners said:
Thanks for all the input guys! The guy I am purchasing it from has owned the 4runner most of it's life and he said he was keeping up with the maintenance on it. I find it a little weird that it doesn't overheat with a bad head gasket.



It does sound like replacing the engine is a better option than just fixing the head gaskets, especially since I plan on keeping it for a while and driving it a lot.
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The 97 puppy hauler either had a coolant leak at the head gasket, left intake manifold gasket, or the coolant bypass tube under the intake. It only ran hot when the coolant got low.

Between gasket kit, timing belt kit, and decking the heads I've got at least 1000 into rebuilding the top end. All the exhaust valves needed reshim'd


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