CPTSOLO

My 2001 GS300 with 2JZGE I6 engine with only 105K miles had a small leak at the radiator. I replaced it with a DENSO rad.

The radiator hoses at the top came loose, engine overheated. I used the original clamp but added another worm screw clamp. Engine ran OK, but after 500 miles the hose came loose again overheated the engine, this time caused major engine problems. Coolant looks OK but oil looks to have coolant mix. Engine runs rough, all cyl misfire, pumping out lots of white smoke. Looks like the valve head gasket is blown or the head may have cracks.

I replaced radiators in my other cars, never had hoses came off. I really like the GS300 and was banking on the 2JZ engine being bullet proof, but this loose radiator hose with 2 clamps is a major screw up. I am so depressed with this simple screw up, cannot think straight. Trying to figure out a way to fix the problem reliably without losing an arm and a leg.

.I have done most maintenance and repairs on all my cars, but never a big job like pulling the head. I got burned a few times by local shops with their low-skilled mechs and stupid tricks and shoddy work, using cheap parts, costing high prices, loss of time and causing lots of head aches. I am afraid any shop will charge a lot of money and not do the repair properly,. so I am considering pulling the head and repair it myself. Please help me out with some advise on the steps I should take, hopefully to salvage this engine and keep it reliable:

1. Pull the head
2. Take head to machine shop for cracks test.
3. Machine head if warped
4. Buy reman head if cracked
5. Buy OEM head gasket, all other gaskets and all one-time use head bolts
6. Follow a good procedure, carefully reassembled head.

I need a procedure to set up the timing belt.

If it's not fixed, tow it to a reliable shop.

Damn, I am so depressed. Would appreciate your support.

LeX2K

You need to check the main and rod bearings, oil/coolant mix makes a very poor lubricant. Last thing you want to do is repair the HG etc. and find out you have rod knock. 2JZ is probably the strongest engine ever made but it uses a composite head gasket which does not tolerate over heating at all.

a few things to consider:
head cannot be machined and returned to service if it is warped more than spec
head is probably not cracked
threads in block must be 100% clean, failure to do this will result in wrong torque readings or stripped bolts
I am not a fan of valve grinds, I lap the valves myself (ask if you want to know how to do this)

CPTSOLO

The main cause of the loose hose was my stupid decision to follow suggestions by a Filipino repair guy in Las Vegas with his Youtube. his Youtube handle is ANGELFIXIT.

His video is still showing, replacing a GS300 radiator, adding a bead of silicon glue on the pipe. The glue must have melted with high coolant temp and became a lubricant, helping to loosen and push the hose out despite 2 clamps. This guy may have intent to harm other DIYers.

Man, I am mad..

DundukovEM

Exactly! This is the reason why your hose became lose. Do not use any lubricants on the radiator hose fittings. Only use a drop of coolant or alcohol spray to put it on. I've had a similar mistake in the past but didn't toast the engine because I double checked it in a parking lot with the engine idling until the radiator fans come on three times. If anything is loose on the hoses, it will spit them out before you get to that temperature. Basically, when pressure (up to 108 kPa) begins to build up in the coolant system.

CPTSOLO

Something caused a strong force that pushed out the hose.

I checked the radiator. It's clean, all the glue was gone. I suspect the glue melted into the coolant and clogged up the thermostat, so when the water pump pumps, it created a strong back force in the blocked coolant to push out the hose.

I cannot believe I destroyed a beautiful engine with my mistake!

CPTSOLO

Looks like it could cause more serious damages.

CPTSOLO

Looks like the glue clogged up the thermostat so when the water pump runs, the back force pushed out the hose. I was desperate and depressed over this simple stupid mistake destroying my engine.

I have a spare car and dont need this car immediately. Without having to remove the entire engine, I should be able to do this job at home. Just take my time and and do it right. Even if it takes 50 hours, that's only 4 days. If the rods knock, will remove the bottom and replace them after.

This guy JOEBOB2385 in Alabama made it sound doable:

https://www.clublexus.com/forums/gs-1st-gen-1993-1997/796788-diy-head-gasket.html

Parhaps I should try the Bar stop leak first. Can;t get any worse.

https://barsleaks.com/product/head-gasket-fix-1111/

I figure things get burned overheating. How do you lap the valves? Please share

Cheezmonky

Are you sure this adhesive clogged your thermostat? Unless you dumped a whole tube of glue in the rad, I'd be surprised if it had any affect on the engine. It did probably contribute to a hose coming off, though. Never heard of using a sealant on a hose connection.

I wouldn't use any stop leak, you'll just be wasting money masking a real problem. The head gasket should not take very long, probably only a few hours. The 2JZ is an easy motor to work on, IMO.

Here's the head removal procedure from my 02 GS manual. If you need any of the other sections referenced, let me know, but I think they're all pretty self explanatory if you just look at what bolts are holding the parts from coming out.

CPTSOLO

Cheezmonky

I think the glue made the thermostat's needle stuck. When the pump runs it created too much pressure and the blocked coolant pushed out the hose, even with 2 clamps tightened around it.. Otherwise where did the force come from?

I plan to replace the thermostat just to make sure.

After reading the comments on Bar's stop Leak, I figured it's just bull****, would cause more problems than it would fix anything. Their guarantee is just the refund for the purchase, not worth anything.

I am thinking of buying the a new gasket set at a Toyota dealer, just to make sure it will last, also the valve cover gasket and any other gasket I can think of.

A poster also suggest lapping the valves. I am thinking of coating the mating surface with a grinding compound, hook the stem to a small hose and a power drill and run them in the valve seats a while. That should make them seal tight.

Thanks a lot for the manual. This is the most complex repair I ever attempted. As long as I don't have to remove the engine, it's worth trying. You gave me the confidence to take on this job and I have time to do it right..

Cheezmonky

One thing to note is that the exhaust manifold does not absolutely need to be removed from the rest of the exhaust, there is enough room to just push it out of the way and work around it.

Those exhaust bolts were nearly impossible to remove, had to plasma torch them out in my case when I had to do it pulling my trans.

You can do whatever valve work you want while the head is off, it is the time to do it. But unless it was an issue before all this, I doubt it's totally necessary.

This job is a good one to get your feet wet in a bit more in-depth repair. It's complex, but you'll be fine. Take pictures of all the timing marks and everything before you disassemble it, for reference when putting it back together. I also have head disassembly and valve inspection sections, as well as head reassembly and reinstallation instructions I'll upload for you when you get there.

LeX2K

Valve grind compound on the valve seat, piece of vacuum hose on the valve stem and on a drill bit. Spin drill slowly back and forth this cuts the valve and seat.

It is much harder doing a job of this scale with the engine block still in the car.

CPTSOLO

Thanks for your suggestions.

Are any special required to take out and reassemble the valves?

LeX2K

Yes you need a special tool, people rave about this one

I use one like this

It is crude but I'm used to it.

Yri

I'm gonna say you're probably not entirely at fault for this happening. I'd say your theory of glue getting stuck in the thermostat isn't all too bad, but it's far more likely for that glue to just get chopped up by the water pump.

You probably had a bad radiator cap and thermostat. Radiator caps are supposed to 'blow off' when pressure gets too high in the cooling system. A bad thermostat could be stuck closed, meaning you'll overheat. Combine the both and you get a recipe for extremely high pressure.

Also, because of the high pressure that your cooling system was exposed to, I would highly suggest watching out for your heater core. Heater cores don't like high pressure, if yours survived mostly unscathed you are incredibly lucky.

FrankT

Replace the motor.
It will be the most cost effective and time saved if you were to source a used motor.
And there is a very good possibility that the cylinder head and the block are warped from overheating.

Good luck