Well this is great!

Coolant level has been slowly dropping on my '96 2RZ-FE Tacoma. Drops maybe half the overflow bottle in 6-700 miles. Very slow. However I can find no evidence of external leaks. I parked the truck for almost 3 days and unscrewed the drain plug until the oil just started to slowly seep past the thread. All I got was good oil, no water. Yay! Then I decide to pull the spark plugs. #1 looks good. #2 looks good. #3 not so much. It looks clean with a little white residue on it and what looks like rust or dried coolant. Also smells strongly of coolant. Great! Got 195 lbs of compression though, so thats good. But somehow coolant is getting into the combustion chamber.

So a little background on the truck...I just replaced the head and head gasket 2000 miles ago. I used OEM Toyota head bolts, and OEM Toyota gaskets everywhere. Also bought a remanufactured head from Allied Motor Parts. Remaned using OEM Toyota casting. Block deck was checked and was flat as can be, also head was checked with straightedge and was dead flat. Head bolts were torqued to spec and I literally checked everything like 5 times before and during installation. Head surface and block deck surface were extremely clean. I did everything possible to properly prep the parts and quadruple check everything. Also, while I have owned this truck it has NEVER been overheated AT ALL. Temp gauge never went above halfway. So I am thinking there must be a) cracked head (I believe most likely, though it was supposedly pressure tested for cracks) or b) blown gasket (I doubt it blew on its own though, everything was perfect when I installed) or c) cracked block (very highly doubt) I do have a 2 year warranty on the head, so I can get another if needed, but what if I get the same problem?

A mechanic I trust recommended I put some Bars Leak pellets in there as its such a small leak. He said theres a good chance it might stop it, being so small. Now if its a cracked head then it might not stop it. So I did that tonight and drove it around for 40+ minutes, got it good and warm. So I will drive it around a bit and see if that stopped the leak. If it did then I am happy, though I know the problem isnt really "fixed''.

Basically I am looking for ideas on what it might possibly be...maybe theres something I havent thought of. Thoughts, suggestions? Anyone?

Thanks!

First pic is what plugs 1,2 and 4 look like. Rest are of #3 plug and comp. test results from #3 cyl.

 

Ok, so a few options.

-Run the engine and watch the top of the radiator fill when reving, tiny little bubbles that swarm with a throttle blip usually indicate headgasket/cylinder head failure.

-Get the engine hot, take the plug out and watch with a pen light on the cylinder, it should pool. A cheap borescope can do this job better.

-Or do it properly,

$32 Lisle 75500 Combustion Leak Detector

https://www.amazon.ca/Lisle-75500-C...ocphy=9001337&hvtargid=pla-293946777986&psc=1

I found this page when I was trying to figure out the name of the chemical tester. They have some good points.

https://www.2carpros.com/articles/head-gasket-blown-test

I would likely forgo tear down on your engine and move on to a used low mileage engine. If the head has been milled once, and is proven to leak, there's no point to try and fix it.

 

Ran the engine an blipped throttle, don't recall seeing any bubbles. Not sure it would pool either, being such a tiny leak but worth a shot. I will see if I can get ahold of one of those testers somewhere. I have basically no other common symptoms of HG failure (no smoke, no oil in coolant in or vice versa, runs smooth, good compression) ...only a small coolant leak really.

Well here's the deal, the heads got a 2 yr warranty so I should be able to warranty it IF that's the issue. Used lower mileage motors gonna run me at least $800 if not more. Head job hopefully only $250-300. Doing all my own work.

 

Any chance the spark plug got the coolant before your head repair? Wondering if maybe the leak is somewhere other than the head. Was it leaking the same amount before the repair?

 

Nope, all plugs brand new at time of head job. I have no clue whether it was leaking before or not because I bought it not running. It stuck a valve, threw a valve shim fragment through the side of the head and banged up the camshaft so I bought a reman headcwith cams. This is not the original head, it's a reman. I had problems originally with cyl 2 having a stuck valve. Now cyl 3 is leaking. Not sure where it could be leaking coolant other than the head/gasket/deck area.

 

Did you ever get this sorted out?


Also, do you have a part number for the head bolts? I'm gearing up to replace my head gasket and realized I need to replace those during this job. Any advice for doing the head gasket? I found some videos on youtube that are pretty thorough. I'm hoping I can get it done in a 3 or 4 day period (assuming the heads are fine). Here's my thread.

 

Well, yes and no. I putput s Bars leak pellets (not in the liquid, dry pellets only) in the radiator. That actually seemed to slow the leak quite a bit, to the point where it's been 800 miles since I topped it off last, and it's less than 1/2" down from the full level. So it may be still leaking, but very very slowly so I am just going to keep driving it. Not really doing any harm driving it as is, it might get worse but then it will be easier to diagnose the problem. A leak this small might be hard to see, and it's a bunch of work to pull the head.

As far as the head bolts part #, I don't have it off the top of my head. I know I found them at toyotapartsdeal.com, just enter your truck info and it will give you the product with oem part number.

Took me 5ish hrs to get it all tore down, but the most time consuming part is cleaning the gasket surfaces. It can be done in 3-4 days easily, but I would make sure you have another set of wheels just in case, because you never know what you'll run into. If the gaskets blown the head could be warped too, make sure you check it with a machinists straight edge at the very least.

Hope I was of some help.