I'm losing a little coolant on my 95 SR5; V-6 with 166K miles. I recently bought the vehicle and have been fixing all the problems. Got most of the big stuff out of the way, I noticed the coolant loss while I'm flushing the cooling system.
With the history of the 3VZ-E, I gotta assume the head gasket is starting to fail since there are no apparent leaks(just replaced all the hoses). No oil in the water or water in the oil, missing or heavy smoke, just the coolant loss.
I don't want to tackle the head gaskets until next spring, so I was thinking of adding something like Thermagasket or K&W Block Seal to make it through the winter. Normally, I don't go for these temporary fixes, but doing a head gasket job in the rain and snow ain't sounding too good.
Any opinions on these products? The K&W is less than $10, the Thermagasket is about a hundie.

 

Do a compression test first or test it somehow.

I would never use that stuff.

Maybe you have a pinhole leak somwhere you are unaware of???

 

No mechanic in a bottle outweighs the risk of screwing your block in the coolant passages...

 

i used that thermagasket stuff it worked for the most part i can drive main roads and the freeway(only for 20miles) untill the water starts getting hott again.) But it works for driving down city streets. i only did it until i got my new engine whichi m putting in soon. But it did work. for the most part. not 100% you cant go up big big hills without it starting to boil over but it will work for atleast a little while. until you do a engine swap. 3.0 or 3.4 swap. or maybe even big boy 4.3.

 

When was the water pump last done?

I would never put that stop leak crap in any truck/car I actually cared about. It will get into all sorts of cooling passages in the block and heads.. don't bother. Unless you are doing a full on rebuild after.

 

sounds like it may not be the HG. compression test it. and i used k&w about a year ago it worked well but ive heard a lot of bad stories and nothing really beats just replacing the thing. my first time replacing a head gasket, it took me about 2 days worth of work, i'd just replace it.

 

if you are gonna do a stop leak, id go with k&w their head gasket bottle is about $25 i think

 

As I mentioned, I normally would not use these sealants, but I don't want to rip the engine apart right now. I'm not sure if it is the head gasket or some other water leak that is not visible, but I'm hoping because it is a small leak, using one of these products might buy me a few months.
The compression is about 140 psi all around, give or take a few pounds, it could be the HG, it could be a coolant system leak, it's something I don't want to see as it is raining now and will be snowing soon.

 

it could buy u a few months, but DO NOT trust it. genies dont exist, and mechanics in a bottle dont exist.

 

Many years ago, I had a 22re that had a small head gasket leak and used kw block sealer. Its a pain to use, alot of flushing involved. I will say the stuff really did work and the truck never burned coolant after that, through a few years of running it. It did however plug the radiator up real good a few days later!

 

Clogging the cooling system would be my #1 concern.

 

how do you like changing your heater core? otherwise irontite by kwik-way $15.99 and you were warned

 

If I use a sealant, I thought I might take the heater out of the loop. Those hoses are kind of hard to get to though, I just changed all of them at the rear of the engine hoping to stop any leakage.
I really don't want to use sealant, at this point it's the lesser of two evils.

 

I'm thinking of trying this stuff on my 510. I dragged it out of mothballs yesterday and found freeze plugs under it and no coolant, bad juju. Runs fine, compression checks out...but I'm getting a bit of water in the oil. Cracked jacket I think. I pulled the head, no evidence of water in the cylinders, gasket looked fine.

I'm going to take the heater core out of the loop and give it a go I think. Since it's not in a high pressure area like the cylinder and I think the leak is a slight crack, I may be OK. I filled the radiator and left the sump plug out with a pan under it, I'm getting a cup of water every 6 hours or so.