Water pump failed, truck overheated and blown head gasket

[redfox]

hi iam new to this forum and read this thread twice as part of my hg research.first time i only read it to the point you got it running and tought everything was great after that for years to come ,second time i noticed that there are more pages on the thread and i am sorry to hear that you had more trouble with it.anyhow you seem to be a patient guy about it.
very nice work on the thread jamie!big help in case i decide to do it.
so here is my story:
i have a 95 t-100 with arund 125k on it which always been great to me never had any major problem and well maintened at least since 98.i decided to fix the leaking valvecover gasket which made a mess of the outside of the engine/i guess this does not fall under "well maintened"/.anyway i got so far into it that the intake plenum is off to get to everything properly,replacing wp and all waterhoses/i belive i found 10 of them/.i am thinking to do hg as preventative maintenance altough never had any problems except for one time when temp gauge went above normal/did not redline/ due to a stock thermostat when coolant was flushed and replace at 85k.and lately water seems to disappear from overflow tank but never looked into this because it was very slow and never seen or smelled any coolant.i believe the hg is still factory.how can i tell if it is not?were all year 3.4's included in the hg recall?i know preventative maintenance for hg may sound unusual but i have big plans for my truck and tring to fix and replace anything questionable. i am going to use the truck in a cross-country rally in amateur class in europe.one of the reason i have chosen this truck was the 3.4 that has enough hp and tourqe.but now i am starting to have second toughts about it especially since i talked to machine shop people and they said this was one of the biggest pieces of crap toyota ever made, they see cracked heads 9 out of 10 and it would be a big can of worm to open .i was shocked when i heard that.anyway i still love my 3.4 it is just so crisp and punchy.
so i would like to hear anyones opinion if should the existing hg will do fine as long as my cooling system does not fail or will a new hg hold up better?
incase i decide to do the job i would like to have questions on the how...
thanks for reading my post

[MTL_4runner]

hi iam new to this forum and read this thread twice as part of my hg research.first time i only read it to the point you got it running and tought everything was great after that for years to come ,second time i noticed that there are more pages on the thread and i am sorry to hear that you had more trouble with it.anyhow you seem to be a patient guy about it.
very nice work on the thread jamie!big help in case i decide to do it.
so here is my story:
i have a 95 t-100 with arund 125k on it which always been great to me never had any major problem and well maintened at least since 98.i decided to fix the leaking valvecover gasket which made a mess of the outside of the engine/i guess this does not fall under "well maintened"/.anyway i got so far into it that the intake plenum is off to get to everything properly,replacing wp and all waterhoses/i belive i found 10 of them/.i am thinking to do hg as preventative maintenance altough never had any problems except for one time when temp gauge went above normal/did not redline/ due to a stock thermostat when coolant was flushed and replace at 85k.and lately water seems to disappear from overflow tank but never looked into this because it was very slow and never seen or smelled any coolant.i believe the hg is still factory.how can i tell if it is not?were all year 3.4's included in the hg recall?i know preventative maintenance for hg may sound unusual but i have big plans for my truck and tring to fix and replace anything questionable. i am going to use the truck in a cross-country rally in amateur class in europe.one of the reason i have chosen this truck was the 3.4 that has enough hp and tourqe.but now i am starting to have second toughts about it especially since i talked to machine shop people and they said this was one of the biggest pieces of crap toyota ever made, they see cracked heads 9 out of 10 and it would be a big can of worm to open .i was shocked when i heard that.anyway i still love my 3.4 it is just so crisp and punchy.
so i would like to hear anyones opinion if should the existing hg will do fine as long as my cooling system does not fail or will a new hg hold up better?
incase i decide to do the job i would like to have questions on the how...
thanks for reading my post

Yes, it was quite a process and just redoing the heads would have worked great if I hadn't had a terrible lapse of judgement and improperly mixed the coolant and it froze (thus blowing my HG's all over again). In hindsight I should have just gone with the Super Long Life (pink) coolant which is premixed and I'd still be driving that other motor today. Anyway the motor I swapped in works like a million bucks and I'm driving the 4runner now because it's better than my 3/4 ton diesel Silverado in the snow (too much torque ).

As far as your problem, I think the machine shop people are either full of it or they are confusing the motor with the 3.0L because the 3.4L is a very solid motor as long as you don't overheat it. Mileage normally isn't a concern on these motors and 125k should just be getting broken in. What does concern me is the coolant disappearing from the overflow tank. You'll need to figure out where it's going in order to be sure it's not head gasket issue (the early 5VZ motors often had coolant leaks at the back of the motor by the firewall). There's a dye you can add to the coolant to find external leaks (using a blacklight) and there's a test you can do on the coolant to check for internal leaks such as a blown HG. The internal leak test isn't always conclusive so if you can't find any external leaks and the internal leak is negative you may still have a blown HG.

You can ask the dealer if your truck ever had the HG's replaced (it will be in their service records). To me, if you were going to rely on the truck for something like a cross country rally and you had questions about the HG, I would probably just go ahead and replace them. At the very least you should be sure everything on the engine is in good shape including water pump, timing belt, idler bearing, tensioner, tensioner bearing, ascessory belts, cam/crank seals, clean MAF, air filter, fuel filter (if fittings aren't frozen), etc. I'd also check other items like steering (tie rods, steering rack, flush PS with ATF) and brakes (check pads/rotors and shoes/drums for wear, bleed brakes).

Hope this helps.

[redfox]

i am glad to read that your 4runner is working good.u deserve it.well i called a toyota dealer and had them check my truck by the vin#.there was no recall or any info on it in their records. it was good news to me.i asked them wich year of the 5vz engine s were recall and they said that they do not go by the year they strictly go by the vin#.the reason for this is because within the same year the made trucks in different plants and wherever they used the wrong patrs those are the trucks that were recalled.just out of curiosity i will call them with two more vin# that belongs to the trucks we drive at work.one is i believe the same year as mine t-100 with about 200k on it and driven by different people with different driving styles over the years if u know what i mean.the other one is tundra with the 3.4 about same mile as mine.
also talked to the mechanic who is helping me to get the truck ready with the suspension and other things.he is also very confident that these engines are great and i should not have to do my hg.so i decided not to disturb this healthy engine any further just fix what i had already torn out.and also i am changing the radiator to a koyo radiator and putting in a liquid filled water temp and oil pressure gauge to better monitor the engine.i will incase have a topend gasket set on hand if i ever have to do it.
today i looked at the back of the engine on both sides as my mechanic also recommended and only found some oil residue which looked like was coming from the valve cover.by the way when i was taking it apart my valve cover bolts were so loose i put the 3/8" extension with 10mm head on it and i could handspin all the bolts.
once iput it back together i will for sure monitor the coolant loss if it will still exist.i will measure compression and do the internal leak test.how exactly should i go about doing this?i am thinking to pressurize it with air before i fill it with coolant so if there is a leak i could start separeting it into different sections and keep pressurizing each one until i find it.what kind of pressure is safe and or good enough to do it with.guessing about 10-15 psi
i would like to attach some pics to the post but i am not sure how to do it

[MTL_4runner]

I am glad to read that your 4runner is working well. You deserve it. Well, I called a Toyota dealer and had them check my truck by the vin #. There was no recall or any other info on the truck in their records. This was good news to me. I asked them wich year of the 5VZ engines were recalled and they said that they do not go by the year, they strictly go by the vin#. The reason for this is because within the same year, they made trucks in different plants and wherever they used the wrong parts, those are the trucks that were recalled. Just out of curiosity I will call them with two more vin# that belongs to the trucks we drive at work. One is I believe the same year as mine T-100 with about 200k on it and driven by different people with different driving styles over the years if you know what I mean. The other one is a Tundra with the 3.4L and about same mileage as mine.

I also talked to the mechanic who is helping me to get the truck ready with the suspension and other things. He is also very confident that these engines are great and that I should not have to do my HG. So I decided not to disturb this healthy engine any further and just fix what I had already torn out. I am also changing the radiator to a Koyo and putting in liquid filled water temp and oil pressure gauges to better monitor the engine. I will, just in case, have a topend gasket set on hand so if I ever have to do it on the road, I am prepared.

Today I looked at the back of the engine on both sides as my mechanic also recommended and only found some oily residue which looked like was coming from the valve cover. By the way, when I was taking the engine apart, my valve cover bolts were so loose I put the 3/8" extension with 10mm head on it and I could handspin all the bolts. Once iput it back together I will definately monitor the coolant loss if it still exists. I will also measure compression and do the internal leak test too.


Use an engine degreaser to clean the engine down and see if just tightening down the valve cover bolts was enough. Worst case installing new valve cover gaskets is very easy and the spark plug tube seals aren't bad either.

How exactly should i go about doing this?

The best way to do this is to do a test on the coolant to check for exhaust gasses. Many times the HG leaks only open up once the engine is warmed up so regular leakdown tests and compression tests will usually come back negative and give you a false sense of security. Bubbling in the coolant reservoir and very hard coolant hoses are a good sign ther might be a deeper issue like a leaking HG.

I am thinking to pressurize it with air before I fill it with coolant, so if there is a leak, I could start separating it into different sections and keep pressurizing each one until I find it.

What kind of pressure is safe and or good enough to do it with?

I'm guessing about 10-15 psi


Yes, the best would be to fill up the coolant system with coolant and then use up to 15 psi to pressurize the system. Most radiator caps will let go above 15 psi so don't use more than that. Also if you can add some dye to the coolant and use a blacklight that seems to work best to find any tough leaks.

I would like to attach some pics to the post, but I am not sure how to do it.


When posting you'll see at the bottom of the post the words "additional options" in red. Ckick on this and you'll see where you can attach photos by browsing to your to your computer for uploading the pics.

I just commented in the text above.

(PS I'm sure you're a younger fellow used to texting, but I fixed the grammar because it was a little tough to read otherwise).

[JOSHH]

I'm about to jump into this, so thank you very much for all the info you have included here.

What kind of special tools do you need besides Torque Wrench, SST Pulley holder tool?

How about the Blue Point tensioner tool? Since I will be taking the tensioner out anyways, do I have any use for this?

Thanks.

[rworegon]

You will not need the tensioner tool. You'll need a in-lb torque wrench and a 250 ft-lb wrench to get the crank bolt torqued.

I found a metric set of box end ratcheting wrenches, a thread chaser set, and a harmonic balancer puller was helpful.