Blowing coolant out the reservoir
12-12-2018, 03:57 PM
#1
Registered User
Thread Starter
Blowing coolant out the reservoir
1987 R22 4x4 carbed.
No overheating issues all summer, but when it got cold I had NO heat. I assumed it was a clogged core, so I did a flush ( both directions with a garden hose at half pressure ).
Flush ran clean in 30 seconds or so, no apparent major clog.
Put it back together and the next trip it ran hot. Didn't redline, but it would have had I not returned home.
The truck has never pegged over half on the gauge.
I suspected air, so I parked it on a hill, gave it a thorough burping....
Ran it all day yesterday no issues.
But, today I did a 10 mile run and parked it. Upon returning I noticed a large puddle of coolant under the drivers front corner. Opening the hood, it was clear it had been slashing a lot ! The reservoir cap was blown off. ( it has never sealed firmly, so, I strung a piece of wire under the tank body and up over the cap to hold it on tight )
While driving in route, the gauge remained around half, at most.
I refilled the rad, took about half a gallon. Took off again, made another stop, same puddle !
Headed for home, but now the gauge started to climb, pulled over at a Speedway, bought some 50/50 and got it home.
Went to Autozone, bought a new OEM type rad cap. No change, still doing it.
Things to note:
The heater core is not leaking.
I replaced the blower motor.
I also disconnected and removed the AC core from the box under the passenger dash to allow for more air-flow. ( The AC compressor has long been disabled )
The air blows warmer but no where near as hot as it should.
I have an exhaust manifold gasket leak. ( it's loud )
The oil looks good, not milky.
The coolant is clear ( green ) no oil seems present.
Truck doesn't smoke.
T-stat is next... but wanted some expert opinions, first.
Sorry for the novel ! Thanks
No overheating issues all summer, but when it got cold I had NO heat. I assumed it was a clogged core, so I did a flush ( both directions with a garden hose at half pressure ).
Flush ran clean in 30 seconds or so, no apparent major clog.
Put it back together and the next trip it ran hot. Didn't redline, but it would have had I not returned home.
The truck has never pegged over half on the gauge.
I suspected air, so I parked it on a hill, gave it a thorough burping....
Ran it all day yesterday no issues.
But, today I did a 10 mile run and parked it. Upon returning I noticed a large puddle of coolant under the drivers front corner. Opening the hood, it was clear it had been slashing a lot ! The reservoir cap was blown off. ( it has never sealed firmly, so, I strung a piece of wire under the tank body and up over the cap to hold it on tight )
While driving in route, the gauge remained around half, at most.
I refilled the rad, took about half a gallon. Took off again, made another stop, same puddle !
Headed for home, but now the gauge started to climb, pulled over at a Speedway, bought some 50/50 and got it home.
Went to Autozone, bought a new OEM type rad cap. No change, still doing it.
Things to note:
The heater core is not leaking.
I replaced the blower motor.
I also disconnected and removed the AC core from the box under the passenger dash to allow for more air-flow. ( The AC compressor has long been disabled )
The air blows warmer but no where near as hot as it should.
I have an exhaust manifold gasket leak. ( it's loud )
The oil looks good, not milky.
The coolant is clear ( green ) no oil seems present.
Truck doesn't smoke.
T-stat is next... but wanted some expert opinions, first.
Sorry for the novel ! Thanks
Last edited by Danny560; 12-12-2018 at 04:05 PM.
12-13-2018, 08:49 AM
#3
Registered User
Is the little overflow tube that bends down the back of the reservoir clogged? It should be open to the atmosphere.
^^ Yes. If no hoses are clogged, I would suspect that the cooling system is over pressurizing due to air (or gases) entering the cooling system when it is not supposed to.
See this video for how to test for combustion gases in the cooling system using a cooling system Combustion Leak Tester:
^^ Yes. If no hoses are clogged, I would suspect that the cooling system is over pressurizing due to air (or gases) entering the cooling system when it is not supposed to.
See this video for how to test for combustion gases in the cooling system using a cooling system Combustion Leak Tester:
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