Do I have a bad head gasket?

[clearock]

As long as the engine wasn't overheated, dont worry about it.

This is completely wrg, even if ur engine was never overheat u should to have ur deck resurfaced when ur using MLS head gaskets. Not only should u have said resufaced but u need to talk with the machine shop and make sure their equipment is up to the job. MLS gasaket require very low RA numbers to seal properly and allow them to function as designed (if ur reading this and don't know what RA stands for then u dont understand and need to read up on MLS gaskets and RA before u just slap them on ur engine), in most cases when rebuilding an DD engine composite gaskets r all u need. You need to make sure the machine shop u use can get the surface into specs or u will be one of the peeps on here talking about how a used toyota engine is better then a rebuild because ur new head gaskets a failing with low miles when compared to and OEM unit, not understanding that it was a lack of understanding on ur part that caused the failure.

 

[rideexileex]

I've done both - pulling the motor and doing HG's with the motor still in. I'd much rather do HGs with the motor in place than pull the whole motor.

Anyway - lot's of the comments I read are speculation based - you need to do some tests.

Do a compression test and see if your motor is still any good / worth keeping. Granted a blown HG can slightly skew these numbers, if the bottom end is good, I personally would feel a lot better with a new HG on a known health block than a 150K ish replacement motor that has X number of miles left on that HG and unknown health.

If the motor is good, take it down to the block surface, and use a mechanic's milled straight edge to test the surface of the block and heads. If in spec, no need to machine the motor, but do definitely clean / prep the surfaces. If not in spec, go to the machine shop. The iron block is most likely fine, and if anything, the aluminum heads will need it if the motor ever overheated.

I think ARP studs are overkill personally... We aren't building race cars here. But that's one man's opinion.

 

[Mackalicious]

This is completely wrg, even if ur engine was never overheat u should to have ur deck resurfaced when ur using MLS head gaskets. Not only should u have said resufaced but u need to talk with the machine shop and make sure their equipment is up to the job. MLS gasaket require very low RA numbers to seal properly and allow them to function as designed (if ur reading this and don't know what RA stands for then u dont understand and need to read up on MLS gaskets and RA before u just slap them on ur engine), in most cases when rebuilding an DD engine composite gaskets r all u need. You need to make sure the machine shop u use can get the surface into specs or u will be one of the peeps on here talking about how a used toyota engine is better then a rebuild because ur new head gaskets a failing with low miles when compared to and OEM unit, not understanding that it was a lack of understanding on ur part that caused the failure.

Can I ask your credentials since you are making that assertion?

 

[APhelps]

Can I ask your credentials since you are making that assertion?

You should always be checking the sealing surface of the heads / block when installing new head gaskets.

I'm pretty certain that its fairly common knowledge that a MLS gasket needs to have lower RA numbers than composite. I posted a link about it as well.

Not sure why anyone would think a used engine is better than a properly rebuilt one either. Machining tolerances aren't a special thing that only Toyota is capable of.

 

[Mackalicious]

You should always be checking the sealing surface of the heads / block when installing new head gaskets.

I'm pretty certain that its fairly common knowledge that a MLS gasket needs to have lower RA numbers than composite. I posted a link about it as well.

Not sure why anyone would think a used engine is better than a properly rebuilt one either. Machining tolerances aren't a special thing that only Toyota is capable of.

9/10 times you don't need to pull your engine and have it decked, unlike what that guy is saying. For our application I will bet your wont have a problem pulling the head and dropping another HG without measuring for warpage unless it was overheated. Then i'd look into things further. Most of the time a visual inspection is sufficient IMO.

 

[clearock]

Can I ask your credentials since you are making that assertion?

u mean like actually work exp. and training... I mean, i never worked on a real vehicle or anything like that, but i did stay in a Holiday inn express last night...

"9/10 times you don't need to pull your engine and have it decked, unlike what that guy is saying"

Peoples reading comprehension amazes me. I never said that u should pull ur engine and have it decked when changing the head gaskets... with composite gaskets, i did how ever say if ur using an MLS gasket (which is the type of gasket that was being discussed) that IMO 1 should because of RA #. The MLS was not used on the 3.4L 4runner until 99. So the factory blocks didn't require an RA # to seal with said and u r running a very greater risk of a MLS leaking. Many machine shops r still running the same equipment from the hay day of rebuilding muscle cars that didn't require an RA to seal properly for MLS (I learned this the hard way) and have seen a # close their doors as of late. My point of my original post is was to inform peeps that may be new to a rebuild and think, "o the MLS is supposed to be better and i want to put the best i can in so i don't have issues". 4 the average 3.4L composite head gaskets r all that is required, and come on forums to read up and think that just because the block was never overheated that it doesn't need to be decked... if they r going to use an MLS.

 

[plcfcng]

I agree with rideeex the only thing that I would do different is I would have the heads done at a machine shop. I have done 4 head gasket jobs in the last couple of years I had great work done in San Marcos at Paradise Motor sports Machine shop. It's worth the money to have the valves cut and heads resurfaced also they reset valve lash. If your heads are cracked I have a couple heads.

 

[Captsolo]

So...I hope I’m wrong...

1997 4runner 3.4l, 212k

Just installed a 1st gen blower on it. I think my head gasket let go.

So before installing the blower, I drained the coolant and thought it smelled a bit like exhaust/fuel. It was filthy also which surprised me being I changed in 2yrs ago. Figured it was old rust buildup that was getting cleaned out. Finished the install of the blower, and after a few hundred miles I’ve developed a cylinder 2 misfire after it warms up. No misfire when cold. Also, coolant just disappears to the abyss. Half a gallon lost after a 20 mile drive. No overheating until the coolant is too low, don’t notice white smoke coming out the tailpipe and also don’t see any fluid buildup underneath or on the engine.


Also, when it’s running there is a steady stream of bubbles coming to the radiator when I have the cap off.

No oil mixes with coolant in either radiator or crankcase

Did my head gasket finally let go after the extra pressure from the blower?

Does it white smoke out the exhaust?
I'd try blue devil HG sealer (Steal Seal) before I swapped another engine. blue devil - Bing video

blue devil - Bing video

Scotty Kilmer 900 million Youtube views HG sealers blue devil - Bing video

 

[T4R2014]

LOL chill. Head gasket sealers are no replacement for a head gasket job.