View Full Version : engine cooling issue diagnoses...help.

El Gato Liso
08-29-2011, 03:34 PM

the thing is, when the engine gets real hot, the coolant get real hot and starts bubbling in the expansion tank reservoir. it gets to the point where there is so much pressure, coolant begins to shoot out of the pressure relieve hose attached to the reservoir cap (the little skinny hose).

why would this happen?

08-29-2011, 03:46 PM
The engine is overheating. Could be a bad fan clutch, thermostat or headgasket (or that could now be the problem as a result).

08-29-2011, 03:56 PM
Check that the radiator is getting really hot.

08-29-2011, 03:58 PM
Start by hooking up your temp gauge

El Gato Liso
08-29-2011, 03:58 PM
the fan clutch works, the radiator isnt hot that i can put my hand on it, it gets hot yes, but its not touching an exhaust manifold hot.

also, the 2 main hoses to the radiator, the top hose is very tight and full of pressure, but the lower hose i can still squeeze.

08-29-2011, 04:48 PM
On the passenger side it should be so hot you can't touch it. You have a lazy thermostat, or a blocked rad. If you say the main hose going into the rad at the top is bulging and hot, you have a blocked rad.

08-29-2011, 04:59 PM
Is the rad old? Sounds like it could be plugged and not allowing heat transfer.

They're not that expensive. I bought mine new from K&H rads in Scarb. I think it was $260.

El Gato Liso
09-02-2011, 02:40 AM
the rad came from richie's parted red e30, its absolutely fine. the lower fat rad hose is just empty, its not deathly hot and i can squeeze it.

i have a thermostat beside me waiting to go in tmrw. ill update you all. wish me luck!

09-02-2011, 03:58 AM
you should start with the cheapest remedy first. Thermostat. Then bleed the system a couple times to make sure you have all the air pockets out of the system. I had the same problem and changed my thermostat. it only helped a bit. I suspect it is my radiator. So I will be changing this. A blocked rad or partially blocked rad could cause this to happen as well.

09-02-2011, 09:22 AM
This is simple. If the fat hose going into the top of the rad is hot and bulging and the lower fat hose is empty and cold, you have a rad problem.

The thermostat must be open at least partially if the top fat hose is getting hot.

Take the thermostat out drill a 1/4" hole in it then pop it back in and see what happens. If there is no change in your situation then this confirms it's your rad.

El Gato Liso
09-05-2011, 04:50 PM
^^^not a rad problem.

the thermostat was replaced and the problem is solved. it felt nice to drive the e30 around town without it blowing the **** up!


09-05-2011, 07:05 PM
You did an engine swap without replacing standard wear items? Let alone times you have no idea of it's condition?

El Gato Liso
09-05-2011, 07:08 PM
^ wasn't an issue for the previous owner. wasn't an issue for the year i drove it with the swapped engine. i am not going to fix something not broken. now its no longer an issue. i replaced a lot of standard wear items. just not the thermostat...which is now replaced.