Water pump failed, truck overheated and blown head gasket

[MTL_4runner]

that sucks jamie.. how many miles do you have on your truck?? also it maybe faulty parts perhaps from dealership?? let us know how it goes

I've been busy with work since I got back so I haven't had a chance to go at it as much as I'd like to. I've got around 140k on the truck right now, but I am convinced the original WP failure and subsequent overheating was really a fluke. The second overheat I have yet to figure out why it occurred. I did a compression test on the motor and all cylinders seemed to have fairly good compression (all were around 165-170 psi) so if there's a leak in the HG at all it's definitely very small to say the least. I also looked at the plugs and they all looked to be burning fairly well (again no obvious signs of an HG leak). I'm going to pull the thermostat completely and see if the truck is still pushing coolant out of the radiator neck quickly and then let it heat up and see if it boils the coolant again. I doubt the thermostat is the problem since I drove it for 40 min to an hour before it overheated the second time (either a bad thermostat or an air pocket in the cooling system should have shown up much faster than that). If it is a headgasket leak then it is indeed very small because there's no smell of coolant in the exhaust (definately nothing visible). I might also try just taking off the valve covers and retorquing all the head bolts and see if that doesn't help my issue without having to redo the HG. I'll figure it out now that it's off the road as a DD (I got my wife a new 2007 CRV EX AWD to drive around in so she's set and then it will be up to me if I want to drive the 4runner or the Civic).

[hillbilly]

(I got my wife a new 2007 CRV EX AWD to drive around in so she's set and then it will be up to me if I want to drive the 4runner or the Civic).

Nice. Good little ride (well, bigger now) for a Mom with little one's up north.

[MTL_4runner]

Nice. Good little ride (well, bigger now) for a Mom with little one's up north.

We like it too, much nicer than I thought they'd be in both handling and finish. It also came with alot of very nice standard features like moonroof, MP3 input, 6 disc CD changer, 17" alloy rims, tire pressure monitor, the list of items is quite impressive. I also like that it doesn't have a huge console in the middle (it has a fold down console tray) which makes things alot easier when my wife needs to head to the back seat to attend to junior while I'm driving. I also like that they no longer use a timing belt (2.4L uses a timing chain) so no worries about the engine getting toasted when a t-belt breaks.

Here's what we got, same color and all:

[Badlands]

Sorry to hear about your misfortunes MTL_4runner!

Hope everythings gonna be okay with your 4runner...but if your looking for a new one...try picking one up from a lease...it's half the cost of a new one and they usually have under 60,000 km on em.

I got mine from a dealer (certified) w 52,000 km for 26K. I agree a new 4Runner (tacoma too for that matter) is outragious!

Good luck with keepin' yours rolling!
-B

[MTL_4runner]

Back to the problem at hand....

Has anyone done a HG on these trucks themselves? Where did you get your parts? Cost?
I'm not sure if they make a HG kit at the dealer or not, anyone know on this either? Cost?

I'm just getting ready in case I need to do one and I have a feeling that the standard HG set from the dealer is going to be very expensive (probably more than I want to sink into the truck at this point). I've seen alot of places selling an Ishino brand cylinder head gasket set which claims to be OEM, but who knows and I certainly don't want to be doing this job twice if I have to do it. I've also found that MLS (multi-layer-steel) gaskets are far more preferable than the standard graphite head gaskets the less expensive kits sell but I've had a heck of a time finding rebuild kits that have these (besides going to the dealer). If anyone has a source for these, post up.

[traxman25]

I too think you should look into the air bubble problem. I've done a lot of work involving the coolant system on my 4 runners and many times I've driven 90-100 miles only to have it over heat again. The FSM will tell you to run with the cap off for about a minute. I no longer follow that. I let the motor run with the cap off until the coolant expands enough to be almost over flowing. That usually solves the problem.

Most times the thermostat goes, esp. if newer, you'll notice the motor over heat a little and then cool off again, and cycle doing so. They normally don't just melt. I think it would be a long shot for an HG to be causing this bad of an issue with out displaying some other symptoms first. IE colored smoke (white or blue), smelly exhaust, rough running, ext.

[MTL_4runner]

Well I replaced the spark plugs today and looked at all the cylinders with a borescope and really didn't see anything unusual or out of the ordinary (the combustion chambers were all very clean and quite carbon free from what I could see ).

The next step was to remove the thermostat which I did and try to see if the vehicle would still build up pressure in the cooling system. The hoses didn't seem to build any unusual amount of pressure running the engine at 2-3k for 2-3 mins at a time. The engine was warming up quite quickly still so I'm not sure what to make of that at this point (leaky HG? bearings? cylinder hot spots?). I'll try and get a leakdown tester and try to pressurize the cooling system and see if those tests are any more conclusive.

[mkgarrison5]

140k miles isnt much big guy.. makes me a little nervous

[MTL_4runner]

140k miles isnt much big guy.. makes me a little nervous

If you're worried then have someone change the waterpump (I still think mine was a fluke left over from when a dealer in AZ screwed with my cooling system.....basically they drained my coolant and put something in which caused my cooling system to rust heavily....likely just plain old water). It was the subsequent overheating after the WP failure that caused the issue I'm dealing with right now. Changing the WP beforehand is cheap money by comparison.

I'm working with Johnny over at sea2sky tuning (in Vancouver) to see if he can get me a good price on an MLS head gasket set for my motor. Then it would be worth tearing the heads off to have a look and make sure everything looks good before I button it all back up and call it fixed.

[traxman25]

(the combustion chambers were all very clean and quite carbon free from what I could see ).

That's actually could be a bad thing at 140K miles. You may be leaking just enough water to steam clean the cylinders.