Chevy Tracker J20 overheating

[testingapril]

I've yet to be able to determine if it is a cooling system inadequacy or engine producing too much heat, but I've replaced the thermostat, water pump, rad cap, and rad. I'm pretty sure that the heater core loop is free flowing, I get heat in the cab.

I've checked with IR gun and it is truly overheating, or at least, borderline. I've also gotten boilovers, but am not currently.

I think my main problem right now is there is air in the cooling system and I can't figure out how to bleed it. Can someone provide instructions? I've tried cranking it with the rad cap off and running at 2500 rpm, but eventually it just sprays coolant out of the funnel violently.

This is the rad cap I bought, I'm concerned it is incorrect because the level in the overflow tank doesn't move when heating or cooling down.

http://www.oreillyauto.com/site/c/detail...&ppt=C0331

[GeoHacker]

I've yet to be able to determine if it is a cooling system inadequacy or engine producing too much heat, but I've replaced the thermostat, water pump, rad cap, and rad. I'm pretty sure that the heater core loop is free flowing, I get heat in the cab.

I've checked with IR gun and it is truly overheating, or at least, borderline. I've also gotten boilovers, but am not currently.

I think my main problem right now is there is air in the cooling system and I can't figure out how to bleed it. Can someone provide instructions? I've tried cranking it with the rad cap off and running at 2500 rpm, but eventually it just sprays coolant out of the funnel violently.

Barring running rich/lean, or you have a bad head gasket, I'd think the engine is just being an engine, so suspect the cooling system?

Mr Fixkick can help more, but I'd verify your cooling fan's clutch is working ok, and maybe change out the coolant temperature sensor too, if that's a potential contributor to anything. (just messes up my idle when cold here though).

It's rare, but new thermostats can be bad on occasion. It is installed in the right direction? There's a hose feel check you can do to know.

If it is air that is in there still, ideal to elevate the front of the vehicle on a little hill or other incline, so it can direct itself up and away. That's how I vented mine after installing a new core. I still seem to hear a few bubbles now and then back in the core, but things seem to be working alright. I did have some close calls when my bypass blew one time (I had bypassed the leaking core) and then once I had the new installed, the old line blew. My head gasket is on borrowed time I worry at times.

This all assumes your head gasket is still ideal and the water pump is pumping.

This video has some generic info:
https://www.youtube.com/watch?feature=pl...vpaTW2WJ5Y

[fixkick]

need more symptoms.
sounds like you fill it up full of water. (50% antifreeze,)then later there is air in the head.
bad headgasket (compression at spec")?

the only trick on the J18/20 is that that hose behind the thermostat must never be blocked. or the thermostat will go nuts.
does it overheat moving fast? (i bet its too scary to try that, but is a clue for the fan clutch dead, if it dont)
in summer all engines overheat parked and idling if the fan clutch dies. so that is always a suspect.
on newer cars that is a test. parked, at what temp does the electric fans kick in,,,,, and same deal.
note how the thermostat is on the engine , backwards, its not at the head hot water exit point, seen at HOSE 1.
this means if hose 22 (and its sources) fail to flow for any reasons, the thermostat has no hope of working right.
the bypass hose might(?) help if the heater core packs up.
ok , you bought the wrong thermostat, almost all stores in my down, 10, sell the wrong stat for your car. they sell you a G16 and they dont work.
tell me your stat maker, and part number.
caused by them not asking your engine vin code, or not even knowing there are 2 engines that year.
one trick is to buy a Esteem thermostat.
http://www.fixkick.com/buy-parts.html#STAT18
the factory stat is 77E00, and that 77 means J18 (and J20)
The "Stant" 14378 is known to work perfectly.

---

WHEN HOSE 22 FAILS (blocked or restricted)
the engine overheats, then the thermostat opens, too late.
then it opens and a flood of cold water hits the wax pellet.
the thermostat then slams shut (cold water) and the cycle repeats. endlessly. (Dr Jekyll and Mr Hyde stat)

[testingapril]

Just did a combustion leak test and it just barely changed color. It seems I have a very small exhaust gas leak into the coolant.

For context it only overheats at 30 mph+ unless I rev the engine a lot in the driveway. I can generally drive it around town as long as I go slow.

The car is not worth enough to justify a head gasket replacement, IMO, but I guess I could get a quote on the job. It's not something I think I want to tackle myself.

Anyone think the Blue Devil head gasket sealer is worth a shot? It's my secondary car, I just use it to go to the hardware store or take the dogs to the vet, so it doesn't have to be able to do anything stenuous.

[fixkick]

ok, so it not the fan dead.
leaving that exhaust leak.
hey give it a shot. what's too lose now? of that devil stuff, or "bars leaks" 100 year old product,
the 2.0L is nice engine, real nice...

so under full load the exhaust puts combustion gas, i the coolant and under load , this is more gas.
under light load , less or no gasses.
it could be a warped head. too. and the gasket was a victim of that, from overheating engine before.

but once a gasket starts to leak, they get worse, there is no stopping this,, sure delayed with the devil stuff.
sorry for your loss and pain.