Coolant loss, yet no signs. ?

[syn-]

Ok, so I have had my OHV for about a year now. Putting some upgrades as I can and dealing with headaches along the way. Though after my latest discovery I am a bit lost (lack of mechanical knowledge). I have a disappearing coolant issue that I am having trouble track down. I replaced the water pump a few months back along with a 180 degree thermostat (I live in the south and was told this helps with my A/C cooling faster.) Since then never seen the temp go up to even close to half unless it became clogged and I would pull over and squeeze the upper hose and turn it back on watch the temp go back down. Now, it doesn't do that as frequent but the other day my reservoir was empty, and when I checked the rad it needed about half of a 50/50 mix I keep around just in case. Now after I drive I can hear the reservoir bubble (its steady) after I turn the truck off, I have a purge valve on my rad cap and can hear a slight hiss near the rubber hose connects to the radiator neck. I drove to lunch today and this is not the first time, but the radiator was cool, I could place and hold my hand there (when my waterpump was bad/still working I could never do that.) I also let the truck sit for a couple of days once and when I lifted the purge on the rad cap it had air in it. ?

 

[vroomzoomboom]

you might have a blown head gasket. when you have the rad full, can you see the coolant bubble?. if you can, get ahold of a pressure tester and pressurize the cooling system to see how fast it leaks down. if your lucky, you will be able to hear air leaking and track it down from there. but i would guess you have a head gasket problem.

 

[syn-]

I have heard some nightmares about replacing the headgaskets on these because it can get costly? when I park the truck, I can hear the hiss at the radiator itself. Be it there is coolant and the temp in Florida now is 30-40, the radiator never seems to get hot like it should.

 

[syn-]

Also, it does not smoke right away when it starts. Usually takes a minute but will have light white smoke while it heats up, never returns till the next morning (as it sits over night). Also, the truck runs fine and only idles funny when I mess with the pressure in the radiator after its been driven for about 10 miles.

 

[mishawaka]

You can check the oxygen sensors to see if they have a green tint. My left bank had a green tint which coincided with the left head gasket leaking.

 

[syn-]

if it was a head gasket, wouldn't I see/feel some problems when it first starts? I would believe maybe I torqued down the water-pump incorrectly or the gasket might have failed. Because the loss is not a lot, I haven't looked @ the radiator recently. I think I might just run it with the cap off today and see if I see fluid. I know one of the bolts needed to be replaced @ the top so it doesn't make the perfect seal if there is one. I did scrape the surface before I put on the new pump.

 

[chewitt272]

syn, check your heater control valve. I'm on my 3rd so far. When you first start the engine, turn on the heater/defroster and look under the hood at the heater control valve. There's a metal rod that potrudes out of the valve body. On mine, you could see the coolant dripping out of there at a pretty good clip, and after a few minutes would leave a pretty good size puddle on the ground.

 

[syn-]

thanks for the clip suggestion first I heard, the cap was the majority of the problem. will be adding a new heater core back into my truck with in the next couple of weeks (mine was looped). sucks for us winter is almost over, but its needed in the morning when your not used to it.

 

[syn-]

Still have bubbling in the reservoir tank after I drive for a bit. Plan on driving it this weekend and seeing if anything sticks out as far as leakage.

 

[Turdle]

These things are a bugger to get "burped"
What you think is a coolant loss could actually be evacuation of air, I am wondering? Is this possible?
It may take several drive cycles to burp all the air from the cooling system once it is cracked open. If you can get the radiator cap higher than the heater core inlet hoses this helps a bunch.
I try to burp mine with the radiator cap off. keep running it up to temp and refilling the coolant with the heater on.

 

[my98nnj]

Also, the truck runs fine and only idles funny when I mess with the pressure in the radiator after its been driven for about 10 miles.

You definately have a blown head gasket.

 

[budwich]

pull and compare all your plugs... you should notice a difference on cylinders that are burning water.

 

[2K2DRSPRT]

Man i'm having the same problems with mine ..

 

[syn-]

Ok, so the surging after the truck is stopped and then started and driven again was a much needed to be replaced fuel filter. the hesitation I was experiencing was in fact the culprit of a much needed fuel filter change. I replaced my serpentine belt as well this weekend, along with one of the hoses on the DPFE sensor. My report, the truck feels great, starts no problem, no hesitation in 2nd any more, no more surging, though I still get the bubbling in the reservoir after I drive. Next step is to pick up some 50/50, let it sit overnight, and actually add coolant and flush out any more air pockets that may still exist from replacing the water pump. To anyone reading this, regular maintenance before diving into other things you'd be surprised.