Losing radiator fluid

[scoots0492]

I own a 2004 SR5 4runner V6. About three months ago I noticed I started losing antifreeze out of the reservoir. There were no noticeable leaks anywhere. About a month later I was on the way home and started to overheat. I took it to the dealership and they said they couldn't find anything wrong with it after performing a pressure check on the coolant system. I now lose coolant fluid faster and constantly worrying trying to keep it filled. What can it be? Could it be leaking around the water pump seal and evaporating on the engine? Or worse am I seeing the beginning of the end with a blown head gasket? Any help would be appreciated since the professional mechanics are saying I am chasing a ghost problem.

Thanks in advance.

Mike
Alabaster, Alabama

 

[rook]

I have not seen any posts regarding head gasket issues on the 4.0 V6. If it pressure tested ok, id take a look at the hoses, perhaps a pinhole has developed.

 

[scoots0492]

Thanks for the assistance Rook. I will check to see if there could be any pin hole leaks.

An additional question I have on the pressure test was could it tell if there was a blown gasket? And if I do have a blown gasket what are some ways I could check for symptoms that I might have? The two that were mentioned to me, were white smoke out of the exchaust (which there is none) and a loss or drop in power (have not noticed).

Thanks in advance.

 

[toto]

I had the water pump problem you describe on a 2000 Tacoma. Coolant was disappearing mysteriously (less and less in the overflow reservoir), with no other signs of a problem. Didn't pinpoint it as the water pump until the truck sat for a couple of weeks without moving, and then there was a visible leak to follow.

 

[gizmopt2002]

Thats screwed up! lol. I have never heard of that happening to a 4th gen. Look at the exhaust when you start the car, if its white then the HG is bad. I would shit myself if the 4.0's had HG problems.

 

[rook]

Thanks for the assistance Rook. I will check to see if there could be any pin hole leaks.

An additional question I have on the pressure test was could it tell if there was a blown gasket? And if I do have a blown gasket what are some ways I could check for symptoms that I might have? The two that were mentioned to me, were white smoke out of the exchaust (which there is none) and a loss or drop in power (have not noticed).

Thanks in advance.

pressure testing can indicate a blown gasket, but it is not the best test.

the easiest method is to have your coolant tested for exhaust gases. other indications of a leaky hg are bubbles in the coolant system and the level in the reservoir may actually go up for a while after topping off. this is due to exhaust gases getting in to the system, displacing the coolant.

for now, just keep the level topped off, checking it regularly. there are many causes of coolant leak, eventually you'll find it. get the combustion leak test done to rule out the hg.

perform regular checks of the water pump, hoses, and the freeze plugs, if you dont find anything, check the heater core.

 

[JP4RNR]

Did they pressure test the radiator cap? You could be losing it through the radiator cap into the expansion tank. If you had a leak there would be noticeable white-pinkish residue from the coolant wherever a leak was present. Coolant also has a very distinct odor.

White smoke when you first start up is condensation. If you have white smoke after driving a few miles after the engine is completely at normal operating temperature you may have a BHG problem. Also note if it real cold out you well get what looks like white smoke as well.

 

[scoots0492]

Thank you all for your thoughts and possibilities! I have it back at the mechanic and awaiting a decision from the supposed "expert." Will report back his findings to the group when those results arrive. Thanks to all!

 

[rook]

any updates?

 

[scoots0492]

So what seemed like an eternity to find it, they finally found the problem. It was NOT a BHG thank goodness!!!!

It was a crack on the thermostant housing that was allowing enough coolant to escape and hit the hot engine and flashed so that you couldn't see the leak. Plus, they couldn't find the leak with a pressure test because they always tested the coolant system when it was cold and with the metal contracted the leak never appeared. Soooooo they replaced the housing (only a dealer part) and the thermostat itself as it was damaged as the crack got bigger. All in all it ended up costing a little more than $225. I have driven it around for almost two weeks and the coolant level has not dropped a centimeter in the resevoir.

Thank you to all for your insights and assistance. Just goes to show that persistence and some expertise goes a long way.

FYI, I asked if it was a BHG what the estimate would be and I was quoted $2400. Talk about a big bill!!!!