Head gasket trouble- time for a top-end rebuild

[mastacox]

EDIT:
The problem seems to have been nailed down to my headgasket going bad (150,000 miles isn't bad), so I'm changing this thread to a documentation thread of me replacing my headgasket and getting some rebuild work done on my heads while they're off.

Well, my 4Runner has been acting a little pissed off lately. I'm glad I got an FSM because I'm fearing a top-end rebuild (or possibly full-engine rebuild) may be in my not-too-distant future Overall the engine's felt a bit sluggish lately, and I'm pretty sure I've noticed some power loss over the past 2 months or so. I'm about to turn over 150,000 miles, and over 100,000 of those have been supercharged so it might be due.

So not too long after I changed to Denso Copper spark plugs (I don't think the plugs are the cause) my 4Runner has been having some trouble with starting. After starting, for the first minute or two it idles VERY roughly, and it feels like one of the cylinders may be having problems with ignition. I can get rid of the problem if I rev the engine up to about 1500rpm for about 20-30 seconds, after which the idle smooths out like all of the cylinders are firing OK but the idle isn't exactly silky-smooth. The plugs are essentially brand-new (I need to pull them to help diagnose the problem) and the plug wires are a little more than a year old with something like 20,000 miles on them.

Additionally, I think I may be burning a slight bit of oil at startup, especailly on the cold mornings that are below 40 degrees or so. It's hard to tell exactly because when you start up the engine on a cold morning you get a lot of cloudy condensation out of the exhaust, but I'm pretty sure I see a little bit of white bluish tinted smoke when I start driving that hangs in the air longer than the white condensation. The smoke and condensation goes away after 1-2 minutes of easy driving once the engine is warmed up. When I got back from Breckenridge last weekend I checked my oil to find it was about 3/4 of a quart low, which goes along with a burning oil theory. On a semi-related note, my coolant is also very slowly going somewhere, I had to put in almost a gallon when I checked the oil but I hadn't checked my coolant in a while.

I have no mixing of fluids between my engine oil, coolant, or transmission fluid as far as I can tell, but I'm planning on flushing my radiator and changing my engine oil and tranny fluid for a more thourough inspection. I'm also going to buy myself a compression tester, if anyone has any suggestions on ones that work well.

[YotaFun]

I am having the same issue fluid wise on my NA engine.
Be interested to see what u find.

I think my oil proplsem is due to a bad PCV.
When udothe flush, use toyota red fluid, I think I mayhave ruinned my system due to using the green stuff.

Other than that I think youhave all ur bases covered

[mastacox]

I think my oil proplsem is due to a bad PCV.

Interesting, I might have to look into that. I'm thinking my burning oil in the morning is oil leaking past the rings overnight and burning off when I start the engine. When the engine is warm or hasn't been off very long, there is no smoke or burning oil smell from the exhaust (although the idle misfire symptom comes back if the engine's been off for an hour or two).

When udothe flush, use toyota red fluid, I think I mayhave ruinned my system due to using the green stuff.

I've been using Prestone Dex-Cool Extended Life with good results, think I'll stick with it.

[YotaFun]

At first I thought it might be blow by as well, but I just felt I should have lost a little more power and blow more smoke then I was.

[MTL_4runner]

Interesting, I might have to look into that. I'm thinking my burning oil in the morning is oil leaking past the rings overnight and burning off when I start the engine. When the engine is warm or hasn't been off very long, there is no smoke or burning oil smell from the exhaust (although the idle misfire symptom comes back if the engine's been off for an hour or two).

I've been using Prestone Dex-Cool Extended Life with good results, think I'll stick with it.

I've just got two comments which might help you Brian.

First, I doubt it would be your rings leaking if you get oil burnoff after sitting for a bit. In that case it could be your valve seals but it's hard to say. It also makes me a bit suspicious of your head gasket since you're losing coolant at the same time. So if the gasket is only sealing when the engine is hot (since parts expand when heated) and leaks a bit when cold (oil pressure jumps almost imediately while parts may take some time to heat up and seal) it may mean you have a boarderline HG issue. At the very least get a compression tester (they're sold all over, Sears, Napa, etc) and see if you can find a cylinder(s) which is/are lower than the others. Also key is to post pics of the plugs (keep them in order of where they came from). If you need to go beyond that, then you may need to have a leakdown test, cooling system test and borescope to find the real issue.

Second, don't use the Dexcool stuff in your truck. It is an organic acid (OAT) formula for long life but it doesn't have the phosphates (as Toyota red does) needed for Toyota cooling systems. Get the Toyota pink (premixed from the dealer). It has the best of both worlds, phosphates and OAT technology for long life.

[mastacox]

Well, the more I study the symptoms the more I think MTL_4Runner may have hit the nail on the head. Even in the relatively warm weather (55 degrees in the afternoon) my 4Runner is putting out quite a bit of condensation for about a minute after start up. I'm talking a James Bond smoke cloud almost (smells somewhat sweet, probably burning coolant).

It would also make sense that if the head gasket were leaking coolant into one or two of the cylinders at startup, it might be preventing proper ignition and therefore giving me my unbalanced roughness at startup. As the cylinders heat up, things expand and seal up better and the cylinders begin firing more normally (although I'm burning coolant for about a minute until the engine starts getting closer to operating temperature.

So I'm going to pull my plugs to help diagnose the problem (and possibly buy a compression gauge off of Summit Racing), but it sounds like I'll be doing a headgasket/timing belt/water pump marathon as soon as I can get the money and parts together (I may bypass the stock tranny cooler while I'm at it). Thank god I bought that FSM, I'd be screwed without it. It will be interesteing to take the top-end of the engine off to inspect things, especially to look for any possible damage to the pistons or valves from being supercharged without a URD kit for around 40,000 miles. It will also be a nice time to adjust the valves (if needed) and possibly get some head work done.

Wish me luck! Any suggestions of things I might look for or replace while I'm in there are greatly appreciated!

[MTL_4runner]

Wish me luck! Any suggestions of things I might look for or replace while I'm in there are greatly appreciated!

No luck needed, been there done that already.......just follow my thread with pics.
http://www.ultimateyota.com/index.ph...6&topic=2241.0

One thing I would have done differently is to resurface the heads so keep that in mind (well worth pressure testing the head, redoing your valve seals and a valve job while the head is apart). Careful taking out the cams, remember the service bolt!!! I also went through factory vs aftermarket parts so read up an save some money in the process too. Just reuse the headbolts if you didn't overheat the truck like I did. Don't use anything but a factory head gasket though, I can't stress this enough. It's a few days work for most people plus machining time so plan ahead, stay organized, don't cut corners and the job won't be as hard as you think.

[mastacox]

Your thread is going to be my bible for this job MTL, thanks for going into such excruciating detail on it. I hope to do the same kind of thing while I do mine.

[mastacox]

So I'm trying to decide if I want to get my heads redone completely, or if I just want to get them machined for flatness and call it a day. I don't even know if there is any place in NM that I would trust to get my heads redone, but if there's anyplace it's probably in Albuquerque.

How likely is it that I'll have to replace the valves? How much does a typical head job cost? Is it really worth getting my heads completely re-done, only to leave the bottom-end alone and possibly have it start going out in another 50,000 miles? I really need to keep this whole deal around $700 or so, which will be tight when I'm replacing the head gasket, head studs, timing belt, water pump, etc.

[MTL_4runner]

So I'm trying to decide if I want to get my heads redone completely, or if I just want to get them machined for flatness and call it a day. I don't even know if there is any place in NM that I would trust to get my heads redone, but if there's anyplace it's probably in Albuquerque.

How likely is it that I'll have to replace the valves? How much does a typical head job cost? Is it really worth getting my heads completely re-done, only to leave the bottom-end alone and possibly have it start going out in another 50,000 miles? I really need to keep this whole deal around $700 or so, which will be tight when I'm replacing the head gasket, head studs, timing belt, water pump, etc.

The entire head job cost me around $350. That included diassembly, hot tanking, grinding valves and seats, replacing oil seals (they come in the Toyota HG kit) and setting valve lash. I didn't have to buy any valves or valve shims at all and I had him reset everything to factory clearances. You will get better gas mileage by redoing the heads and you'll have to strip them down anyway to be resurfaced.....IMHO it is worth redoing them completely. To find a place for machine work, call your local Toyota dealer and ask who they use for their machine work.

Your bottom end is likely fine, but it's impossible to know before you tear it down. Yes, $700 will be a tight budget for that, more like $1000 but remember if you do it right the truck will be treat you well in the long term.