318TI Rad in M50 E30 passenger side of rad cold

[5mall5nail5]

Hey guys - this is so annoying and I can't figure it out. I am thinking maybe I have the heatercore lines backwards... maybe?

I have even gone so far as to use my AirLift II vacuum coolant bleeder. But... no matter what I do, the passenger side of the radiator (the side nearest the exhaust for the non US cars) it cool to the touch and the hose seems to have nothing/not much in it.

Any advice?

[FredK]

This style of radiator is probably the hardest to bleed. I once just filled one up to what I thought was appropriate, bled it some, went for a test drive, then I noticed that the coolant temperature was creeping up. So I pulled the cap which was a tremendously BAD idea, and cold coolant shot like 3 feet into the air.

The only way I was able to bleed it was to pull the thermostat and drill a small hole (around 3/32") at the top of it, and bleed with the expansion tank cap off, heat on high, blower on high, and hold engine speed at 2500 rpm or so. I didn't have to elevate the front of the car.

Heater core hoses should be spider top head bottom.

[Adrian_Visser]

Why not ask on Bimmerforums FI? I guess you're too busy playing expert there to ask such a simple question?

[5mall5nail5]

This style of radiator is probably the hardest to bleed. I once just filled one up to what I thought was appropriate, bled it some, went for a test drive, then I noticed that the coolant temperature was creeping up. So I pulled the cap which was a tremendously BAD idea, and cold coolant shot like 3 feet into the air.

The only way I was able to bleed it was to pull the thermostat and drill a small hole (around 3/32") at the top of it, and bleed with the expansion tank cap off, heat on high, blower on high, and hold engine speed at 2500 rpm or so. I didn't have to elevate the front of the car.

Heater core hoses should be spider top head bottom.

Yep - confirmed my hoses were spider top head bottom. Pulled the thermostat out this afternoon and thew it and an extra in some boiling water. Not sure on the brand that was in the car, but its 88C. I put it in a pot with a Vernet 88C and they didn't seem to open when sitting in boiling water. I put the Vernet new one in with a 1/16" hole drilled. Seems a little better, the passenger side hose is now warm/hottish, but I feel like it's not opening or is too high of a temp before it opens for my comfort level. I use a 75C in my E34 and like how it opens - it's easy to bleed since it opens at a lower temp. Going to try that out. I love the integrated expansion tank too much to put in the lamer M20 rad. I realize they can be a pain but I have had no issue on the other 3 cars I own :( Thought I might have had the heater core hoses backwards but it seems not (though there's rumor that the valve on some cars is mixed up... sigh).

Why not ask on Bimmerforums FI? I guess you're too busy playing expert there to ask such a simple question?

Yeah that's me, pretending to build cars and such.

Too funny. Pretending. Ah. If only. Don't be angry because your car is slow.

[Roysneon]

Try pouring as much water as can fit in the rad and both the hoses, then fasten it all down and bleed that way? That's what I did with my M20 rad and it worked when nothing else would. Stock spec E36 M50 thermo.

[5mall5nail5]

Try pouring as much water as can fit in the rad and both the hoses, then fasten it all down and bleed that way? That's what I did with my M20 rad and it worked when nothing else would. Stock spec E36 M50 thermo.

yeah I used a vacuum bleeder which should really be the end-all. I feel like the t-stat I have stinks. I'll update when i receive the new one next week.

[mentaleeill]

Why not ask on Bimmerforums FI? I guess you're too busy playing expert there to ask such a simple question?

or, why not ask on an e30 based forum, in the dohc swapped subforum, where the 318 rad and its issues are common knowledge?

jon, just hold the idle up at around 2500 as previously stated, with the heat on high,the bleed screw open, and reservoir cap off. you gotta really force the coolant in there as well.

[Jand3rson]

I just had an issue bleeding mine properly recently, which is strange, because the first time it bled no problem. I think I had an air bubble right in the area where the fan switch sensor is, because my fan wasn't coming on. We thought maybe the switch had gone bad, so we replaced it, but when we pulled it out, no coolant came out of the hole. So I jacked the driver side of the car up good and high, and ran the car for about 20 minutes with the bleeder screw threaded almost all the way out, gave the hoses a bunch of good squeezes, (even smacked the side of the rad with a rubber mallet a few times :D ). Eventually it bled, because the fan started coming on again.

I REALLY wish someone made an aftermarket M42-style radiator, because I'd love to upgrade, but maybe I'll just have to bite the bullet one of these days and go Mishimoto, and have the external expansion tank again.

[5mall5nail5]

or, why not ask on an e30 based forum, in the dohc swapped subforum, where the 318 rad and its issues are common knowledge?

jon, just hold the idle up at around 2500 as previously stated, with the heat on high,the bleed screw open, and reservoir cap off. you gotta really force the coolant in there as well.

Thanks Bobby - I powder coated an extra t-stat housing I had and have the new lower temp t-stat coming in. It will make bleeding easier as it should open a little sooner. I will give that a shot. Have a super steep hill on the driveway I can drive up on and see if that helps. Thanks again.

[RobertK]

Are you 100% certain the water pump is good?

Steve had this problem with his M52 swapped E30. Turned out that the water pump was toast so even though it was spinning there was no flow. Exact same issue you're experiencing.

[5mall5nail5]

Waterpump is new, so I would think it's good but I have seen crazier things happen. I will try the lower t stat and such and then pull the pump and see.

[RobertK]

Waterpump is new, so I would think it's good but I have seen crazier things happen. I will try the lower t stat and such and then pull the pump and see.

Might try it temporarily with no tstat just to confirm WP flow. If you're still running cold on the passenger side then you definitely have coolant flow issue.

[5mall5nail5]

Thanks to everyone for their constructive input (some more than others lol).

So, it turns out the water pump is pumping away which is good. I made this out of one of the suspect t-stats:


Water pump flow tester by Jon Kensy, on Flickr

Left the lower rad hose off with that hollowed out t-stat in and it pumped water very well with a garden hose in the expansion tank. So, ruled that out.

Swapped in the 75C t-stat after testing it in boiling water. Neither 88c unit opened in boiling water, but the 75C opened a full 3/16 - 1/4". Drilled a 3/16" hole in the top of the t-stat and slapped it together. So, bled and bled, running the car expansion tank open w/ bleed screw open revving it around and I think I got all the air out (I would have used my vacuum bleeder but wanted to try conventionally first). The car seems to be bled and holds good idle temp and starts creeping (95F here today and very humid). Once driving, the car stays just below midway. If I park it for a couple mins it'll start creeping up. So, that's exactly what I would like to see vs what the other t-stats were doing which was simply running hot all the time even rolling.

So, now up is better electric fan than what the factory aux fan does.

Going to measure tomorrow for clearance and see what might fit behind the radiator.