Hey guys/galsI will give you as much as I can to help you diagnose my problem without being to long winded.1995 Toy 4runner3.0 2wdAutoI recently bought the truck with a small line of red antifreeze on the tranny pan. I thought at first it was tranny fluid no it was antifreeze. I went to the engine and thought the leak was coming from the radiator hose housing on the top of the motor. pulled it no "o" ring just silicone. I replaced and then noticed leak more predominate and at the intersection of the head and intake above #1. I watched the levels and drove it for a few more weeks collecting parts. I could drive for 30 min and if I stopped the water temp would climb to red area then pop it into neutral rev it and it would drop back to normal. This weekend I had enough. I did a t-belt, water pump, t-stat, plugs, and both tensioner pulleys. Upon disassembly I found the t-stat had the bottom cut off, so there was no t-stat really, I found that it had a water pump and t-belt done. buttoned it up and test drive. Small interjection; I live in Denver where it was 5 degrees when I test drove. I started it no problems got it on the road within 10 temp was in the red and antifreeze steaming from the front. Babied it home and researched boiling coolant and I come up with HG. I did a compression test today and every cylinder is 120 +/- 5lbs. I did not warm it up, I forgot. Also I did not notice white smoke during the test drive, as it was freezing and the exhaust I saw was normal for the temp I thought.I was expecting different numbers from my compression test. I want to lean towards the HG but I don't want to get a set of HG and Head bolts and after it is done have the same problem. All advise is welcome. Thanks in AdvanceGeoff

 

I'm no expert on HG, but there's a few things to check first.

Check your dipstick. Any discoloration/spots (looks like coffee w/ creamer in it) means water in the oil. That is a definite sign of a HG issue. Same goes with oil in the coolant. A "sweet" smell from the exhaust means you are burning coolant, which is also a sign of a HG problem.

Next time you run it, see if any other hoses to/from the radiator feel cold. It could be a blockage somewhere in the coolant lines causing poor circulation and overheating. That could be as simple as a new hose or t-stat, instead of an entire upper engine rebuild. Did you ever put any stop-leak or additives in the coolant?

 

Just because the pump looked new doesn't mean it is, and doesn't mean it's functioning properly. I would of changed it anyway since you had it torn down and the parts in hand.

Did you forget to use sealant when you put in the new thermostat gasket? Needs sealant or they will leak, it could also of been damaged.

Did you do a visual inspection to make sure the broken thermostat piece wasn't lodged in the motor housing or sucked into?

Did you test or replace the radiator cap? If the system doesn't build pressure it will boil sooner.

Once it's properly warm there shouldn't be any significant ammount of smoke or vapor apparent. Meaning once it's warm at the back all the condensation in the pipes should be gone so little to no steam.

Oil in the toyota (red) coolant is a little hard to spot, but water in the oil is going to be apparent.

Call around to the toyota dealerships, have your VIN handy, and find out if it was serviced under the recall, if so when, and are they willing to fix it under the recall program or warranty.

Once you've eliminated the coolant lines and connections, the only other thing it could be is the head gasket. Yours appears to be the good kind of failure at this point, eg leaking out of not into the block, don't drive it or it's gonna cost alot more to fix.

 

Check your dipstick. Dipstick is clean and is the coolant

Next time you run it, see if any other hoses to/from the radiator feel cold. I will check that next time.

Did you forget to use sealant when you put in the new thermostat gasket? Needs sealant or they will leak, it could also of been damaged. TStat had the "o" ring that went around the tstat no gasket

Did you do a visual inspection to make sure the broken thermostat piece wasn't lodged in the motor housing or sucked into?Tstat was not broken someone cut the bottom off very surprising

Did you test or replace the radiator cap? I will have that tested

Once it's properly warm there shouldn't be any significant ammount of smoke or vapor apparent. Meaning once it's warm at the back all the condensation in the pipes should be gone so little to no steam. did not think about that

Oil in the toyota (red) coolant is a little hard to spot, but water in the oil is going to be apparent. changed over to the green

Call around to the toyota dealerships, have your VIN handy, and find out if it was serviced under the recall, if so when, and are they willing to fix it under the recall program or warranty. Checked no luck there

Once you've eliminated the coolant lines and connections, the only other thing it could be is the head gasket. Yours appears to be the good kind of failure at this point, eg leaking out of not into the block, don't drive it or it's gonna cost alot more to fix.

No plans on driving just want to get it fixed w/o throwing crazy money at it. I had thought the coolant was leaking at the intake manifold because of a failed intake gasket but there might have been other reasons as to why it failed.

Geoff