Toyota 4Runner Forum - Largest 4Runner Forum (2023)

That's a good idea

Toyota doesn't "need" to do anything about the HG failures. IF they do anything, it will be out of goodwill, like the cracked dashboards...

A HG failure is not a safety issue, it's a QDR issue.
Over the life of the engine options for the 4th Gen (v6 or v8), the maintenance expenses probably even out.... HG failure possibility (on the v6) vice multiple timing belts (required), secondary air pump failure (possible), and cracked manifold (possible) (on the v8).

Luckily for us, Toyota prides itself on QDR across its lineup, which is probably why the made the change in Nov 2005 to improve longterm QDR on the 1GR-FE (this won't be known for another couple years though based on how many 2006 and up 4Runners HG fail)...

It's also why if you look at the new engine design details (for instance the new 2GR-FKS engine usedin the Tacoma and GS350), they address uneven cylinder cooling and the thinner width of the HG between cylinders during assembly. (see attached)

When you have HG failures happening at 120,000 miles, yes they need to do something. It's not just the 2003 - 2006 4runners, it's also happening with the 2005 - 2006 Tacomas. It happened to me 3 times with 3 different 4 runners in the last 12 months, I would call that a problem. They had a recall for the 3.0 and the 4.0 is just as bad. Overall, Toyota makes a great vehicle, that's why we have 7 in our family, no argument there. I was talking to the service manager at our local dealer and he said he's had at least 6 4Runners come in the shop in the last 4 weeks with bad HG and Toyota will not help out. Timing belt service is $650, HG job is anywhere between $2500 - $3400, you can do several timing belts for that. to be exact, you can do 4.5 timing belts for the cost of one HG job ( $3000 average cost ), that's 405,000 miles if you figure each TB change at 90,000 miles.

I just replaced the head gaskets a couple weeks ago. I didn't have misfires or check engine light, just lost coolant out the overflow tank after highway driving and towing. It was somewhat having the issue at 125k when I bought it over two years ago but would lose the coolant slightly faster more recently, and i finally replaced the head gaskets at 152k.

2004 4.0 V6
Production date 07/04
4x4
there was a pitted area between cylinders 4 and 6 on the head.

I did a bit of a writeup here: Head gasket repair on 4th gen 4runner V6 - Expedition Portal

:spam2::spam2::spam2::spam2::spam2::spam2:

Good luck to you. I hope that works out. I don't think that it's likely to be a long term solution.

2004 SR5 V6
236K miles
Cylinder # - will find out this weekend
Manufactured 04/04
Plant Code 8
Couldn't locate the EIN

I've determined that I believe I have the HG issue. Fdbryne gave me some good advice and I'll have my local autoparts store pull the codes to confirm.

All the same issues - hi temp led me to discover loss of coolant. Rough idle at startup, CEL and issues worsened. I found this site and deduced the HG issue based on symptoms. That and I used a bottle of Blue Devil HG seal and it seems to have temporarily abated the problem. At least to the point I can operate the vehicle without the sputtering.

Somewhere up in the thread someone posted the front timing cover oil leak, and while out looking for the EIN, I see I have the issue as well. I have oil leak/stains exactly where the bulletin says to look.

I have to admit I had poor maintenance on the vehicle. I believe that was the original coolant that I lost to leakage starting a few months ago. Oil changes, brakes, tires, air filter, etc yes. Oh and the A/C had to be replaced at roughly 100K.

My local auto parts shop had the code scanner stolen? Who does that?

Anyway, is there some significance to the fact that this rough idling and rough running doesn't really occur unless the car is in gear? It doesn't replicate the problem when it's in park or neutral and.

The car is no longer leaking water so I assume the gasket has been sealed with that blue devil product I used. My local Toyota service center is clueless about these head gasket issues, They never heard of such a thing as we've been talking about on this blog. I have to travel a little further to a larger Toyota dealer with a bigger service center.

You should check Amazon. I got mine for $30 it's wifi and runs of an app for iPhone. I also use it to monitor the exact temperature. Helps to ease the worries of weather the gauge was accurate. It stays always stays in the normal temp range after it warms up.

I change mine out every other year. It's very very very cheap insurance of having a head gasket failure.http://to.ly/X03mhttp://to.ly/X043
http://to.ly/X041

2004 4.0L 1GR-FE 4x4 SR5
203,000 miles
mfg date 02/2004

Head gasket being replaced now @ 203K miles, cylinder #6

What were you quoted on price for the replacement? Any signs that it was happening to you?