First drive, overheating, bleeding issues?

[bacain32]

So I took my car out for the first time tonight since finishing the swap. Everything has gone great until tonight, engine runs perfect, no problems or CELs, but as soon as I got it out on the street, the temp gauge just went climbing. I shut of off about the 3/4 mark. Car is an S50 swapped '87 325is, M42 radiator, heater connections hooked up correctly, I verified the heater valve inside the car before even hooking them up. Electric 1300 cfm fan, working properly. The car wouldn't put out any heat, the radiator and lower hose were as cold as the day I put them in as well after driving. Does this sound like a bleeding issue? I took the waterpump and thermostat out and checked them just to make sure those weren't bad and put it all back together, still getting hot. I'm stumped now. Any advice is appreciated!

[328ijunkie]

M42 radiator. = Problem.

[bacain32]

I've done a bunch of searching tonight about this, seems like they're a pain in the ass to bleed properly.

[SpeedRacer85]

Did you ever find out the problem, looking at getting a m42 rad.

[bacain32]

Hoping it is just issues with bleeding it. I have the front of the car jacked up 2 feet off the ground. I really hope it helps. Seems the expansion tank went almost empty when I put it up.

[bacain32]

Tried bleeding again today, no luck same shit

[lolcantturn]

1.Raise front of car 1 foot
2.Turn on car
3.open bleed screw and coolant cap
4.heat on blast
5.go inside your house and grab beer
6.come back outside in 20minutes
7.check temperature
8. Good? If yes repeat step 5, then go to step 12. if not go to next step
9. let engine cool down
10. With your right hand on the throttle body and your left on the rad hose, rev the engine up to about 2000rpm and start squeezing the upper rad hose with the bleed screw open. prepare for molten coolant lava to spew all over your arm from it erupting from the bleed screw. Then let it idle and squeeze the lower rad hose a billion or so times.
11. close bleed screw and coolant cap and rev your engine to 3500rpm for about 10 seconds, if you don't feel heat by now then you have an error somewhere in your cooling system, probably the thermostat.
12. Now that you have heat you can now properly let your car bleed at idle without worry. Open the bleed screw and coolant cap and let it idle for about 20 minutes. Squeeze rad hoses.

M42 isn't THIS hard to bleed, but this is as difficult as it should get. Normally you can just let your car idle from cold with the heat on blast and the bleed screw and coolant cap open and it will bleed itself. They are not problematic radiators like people think they are.

[bacain32]

That's exactly what I did. I squeezed the hoses till my arm hurt. Still no heat, radiator ice cold. Thermostat is even out right now. Thinking possible radiator blockage.

[treff-7]

have you checked your water pump? you might have a broken impeller. even if the radiator is blocked i think the hoses should get at least warm.

how long did you let the engine run? are you sure you have the right temp sensor for your gauge?

[trackjunkie21]

M42 radiator. = Problem.

Nope, as long as the bleed screw isn't busted it isn't difficult at all, bled mine many times and a few others.

[bacain32]

Got it figured out finally. The spider hose off the engine is only so high compared to the radiator expansion tank to allow for proper filling. What I did was took the top radiator hose off, and filled the engine through that. Put the hose back on, filled the rest of the radiator, then bled it, worked perfectly. Heat is blazing hot, fan is kicking on and working great as it should, it's an 82/87C switch. The only thing is the temp gauge reads almost 3/4, BUT with an infrared thermometer, the thermostat housing is 178 degrees, the hoses are 173 degrees and the radiator is 174 degrees. SO its really all working as it should, just the needle reads high, but I can live with that.

[mattrabbit]

When you did the swap, did you change out the coolant temp sensor for the one from an e30? If not, that might be your gauge problem.

[bacain32]

Yep sure did

[SpeedRacer85]

Cool beans on finding the problem thats how I filled the m20 back in the day cause there is not rad cap nice. I got to buy me a m42 rad now to clean up the engine bay.

[Jand3rson]

M42 radiator. = Problem.

Haven't had a single issue with mine, and as usual, more people constantly bitching about how hard they are to bleed, I've done mine 3 times without issue.