boiling coolant and overheat help plz!

[e30 vert]

hi

so after i saw the coolant is boiling and steam coming out res tank and i find a coolant leaking inside(driver side) the car i thought the heater valve is leaking and causing low pressure in

coolant system so today i bypass the heater valve by connecting the 2 coolant hose before hv together but it didnt solve the problem but this time i saw steam coming out from back of

the engine and less steam from res tank as my tem gauge doesn't work i couldn't see how hot the engine is also the check engine light came on and after a few min car stalled .when the engine was running i check the upper

rad hose it was hot but soft i did some research but couldnt find right answer for it and how to inspecting a water pump and thermo

any idea what it could be and how to inspect those parts

its a 92 vert with m42 and i didn't drive it engine was on idle

thanks

[mikeedler]

thermostat and/or water pump probably. pull them both out and have a peak.

odd for a car to push coolant out of the system and not have rock hard hoses.

[e30 vert]

thermostat and/or water pump probably. pull them both out and have a peak.

odd for a car to push coolant out of the system and not have rock hard hoses.

so the coolant hoses needs to be hard when the engine is running ?

[vpilarrt]

I answered you on your other post but here it is again:

First thing to do is fix your temp gauge - its critical to the life of your engine.
Second thing is to check the fan clutch.
Third thing is just to go ahead and replace the thermostat and bleed the cooling system.
Water pumps do not wear out but they can fail - either the seal leaks (you'll see antifreeze running out around the shaft) or the impellar breaks, if it has a plastic one.

[sweet3]

The cylinder head is most likely warped and cracked. Your coolant issue won't be fixed unless the head is pulled and repaired. I would definitly go ahead and replace any suspicious hoses and the thermostat. I would also advise replacing your water pump if it has plastic fins.

[mikeedler]

so the coolant hoses needs to be hard when the engine is running ?

If it is pushing the coolant out, then yes, the hoses should be rock hard as it is doing that, if not, it could be something as simple as a bad cap.

The cylinder head is most likely warped and cracked. Your coolant issue won't be fixed unless the head is pulled and repaired. I would definitly go ahead and replace any suspicious hoses and the thermostat. I would also advise replacing your water pump if it has plastic fins.

I think there are alot of things to test before just ripping a head off of a motor?????????????

and like previously stated, FIX the coolant gauge NOW!

[isamemon]

yes fix the gauge, but you can use a thermo gun on the block to check heat. check at thermostat housing

other things....a hose on the prehater for the throttle body ( get rid of that junk)
the plastic pipe or one of the hoses coming off of it. ( bel0w intake manifold, again driver side)
fan clutch, I doubt it..besides they have an aux fan that should kick on if working
running a 91 vert m42 wiht no fan or fan clutch, only aux fan, and it has never run hot on me

[e30 vert]

I answered you on your other post but here it is again:

First thing to do is fix your temp gauge - its critical to the life of your engine.
Second thing is to check the fan clutch.
Third thing is just to go ahead and replace the thermostat and bleed the cooling system.
Water pumps do not wear out but they can fail - either the seal leaks (you'll see antifreeze running out around the shaft) or the impellar breaks, if it has a plastic one.

thanks for the help

when i turn the key on the gauge will move but when i start the car it will go back on cold and not moving since the rad hoses are soft when the engine is running im thinking the thermo is bad

also is thermo do anything with tem gauge ?

i've heard there is a ground cable in the cluster that become loose ?!

[kwill22]

The nut that holds the temp gauge in place can possibly come loose yes but I personally don't think that's your problem. the signal is received from the sender in the head, under the intake manifold. You have to take the upper part of the manifold off to get to it and I believe loosen the lower manifold.

There will be 2 sensors screwed into the head. The sender for the temp gauge is the sensor on the right. Go ahead and replace them both while you're at it. They're pretty cheap.
(The sensor on the left can be accessed without removing the intake manifold FYI)

[e30 vert]

The nut that holds the temp gauge in place can possibly come loose yes but I personally don't think that's your problem. the signal is received from the sender in the head, under the intake manifold. You have to take the upper part of the manifold off to get to it and I believe loosen the lower manifold.

There will be 2 sensors screwed into the head. The sender for the temp gauge is the sensor on the right. Go ahead and replace them both while you're at it. They're pretty cheap.
(The sensor on the left can be accessed without removing the intake manifold FYI)

what are they called?

[bmwman91]

The cylinder head is most likely warped and cracked. Your coolant issue won't be fixed unless the head is pulled and repaired. I would definitly go ahead and replace any suspicious hoses and the thermostat. I would also advise replacing your water pump if it has plastic fins.

This is exactly what I thought when I read the thread title. "Boiling" bubbles in the coolant when the engine is running are almost always due to combustion gasses getting into coolant passages. If the coolant system already had issues and the engine overheated, the head is almost guaranteed to be warped.

OP for your sake I hope that the issue turns out to be something mundane. It sounds like a head issue to me though.

[e30 vert]

This is exactly what I thought when I read the thread title. "Boiling" bubbles in the coolant when the engine is running are almost always due to combustion gasses getting into coolant passages. If the coolant system already had issues and the engine overheated, the head is almost guaranteed to be warped.

OP for your sake I hope that the issue turns out to be something mundane. It sounds like a head issue to me though.

the engine came out of e36 and when i bought it the guy did the compression test and was all good

[e30 vert]

i think something is wrong with water pump or thermo cuz when the heater valve was on the car all the pressure was coming out from there now i bypass that its coming out from some where else and the rad hoses are soft

[bmwman91]

the engine came out of e36 and when i bought it the guy did the compression test and was all good

Did he do a leak-down test? That is more relevant to this issue.

[e30 vert]

Did he do a leak-down test? That is more relevant to this issue.

no but im pretty sure the engine it self is fine



so today i let it warm up again and loose the bleed bolt on the top of the radiator and that was the only place that i saw steam was coming out


i was trying to stop the fan while the car was warm and it stopped easily so the fan clutch is bad



and i checked both coolant hose that are connect to the thermo hose the driver side was hot and the passenger side was COLD so the thermo is bad ? or water pump ?