Author Topic: clogged radiator? (Read 6106 times)

jdirty · « **on:** October 04, 2011, 02:03:02 PM »

how can one tell without taking it off and backflushing(?) it?
i recently put in

a new head (shaved and valve job) because the previous head cracked.
new headgasket
fairly new thermostat
and i bypassed the heater core as well.

i bypassed the heater core because i wasn't so sure what the hell was going on.
originally the pipe coming from the side of the block was plugged in the lower heater core pipe and the other coolant hose that's coming from the end of the block was plugged on the upper coolant pipe on the firewall.
the lower one was cold. i tried swapping them. which did the same thing with the same hoses, one of them were cold. so i just assumed that the heater core(and or valve) was shit. so i bypassed it and connected the two hoses together.
i noticed that the two rad hoses upper and lower were both hot.
so that means the thermostat opened right?
i proceed to rebelled the cooling system.
i noticed that the bleeder screw at the bottom, though screwed tightly shut, was still dripping. wtf?
till now my temp keeps going 3/4 like how the car was before the original head cracked.
at this point i'm not too sure if it's the radiator or the temp gauge fucking with me. i really really don't want to risk running 3/4 temps given that my head is new.

any ideas?

DesktopDave · « **Reply #1 on:** October 04, 2011, 04:08:37 PM »

I'd drain & pressure test the cooling system. Those little test pumps aren't much at Harbor Freight. If you're not getting proper system pressure, the car will overheat. That little bleed screw might be stripped a bit too.

There is a recall for the e30s regarding a bypass valve installed in the heater supply lines. It connects the two lines with a bypass valve to prevent the heater core from rupture.

I'm not totally sure that the system pressurizes to 15psi (1 bar) or 30 psi (2 bar)...I've seen markings on the cap that others tell me is for 30psi. If so, make sure you get a pump that'll pressurize up to 30psi.

jdirty · « **Reply #2 on:** October 04, 2011, 08:52:02 PM »

i think i was looking at the bypass valve earlier. lol probably stuck. i ended up bypassing the heater anyway. would be nice to hae heat though.

would you say that the bleeder screw would cause pressure loss?
oh yeah i got a hold of an infrared temp reader thing too.
i dont know the values i should be looking for though.

DesktopDave · « **Reply #3 on:** October 04, 2011, 09:44:22 PM »

I have my car running with a 90degC thermostat, so I'd figure that you're looking for about that at the thermo housing, though a lot of M42's have 82degC stock IIRC. Just post what you find...take some temps at the thermo housing, cylinder head, both sides of the radiator, coolant manifold, etc.

How's the fan clutch and aux fan? Both working, right? My car was overheating recently and I discovered that the aux fan wasn't working at all...on either speed. Ended up that I had a loose fuse and a bad resistor pack. Car still runs warm, but not uncomfortably so.

jdirty · « **Reply #4 on:** October 04, 2011, 11:29:19 PM »

fan clutch was recently replaced as well.. as for the aux fan.. it turns on when i turn on the ac. but even though the temp gauge was reading 3/4 i don't believe the aux fan went on when i was trying stuff out earlier.
i should double check on that aux fan later.

DesktopDave · « **Reply #5 on:** October 05, 2011, 09:26:09 AM »

Check the fanstat on the side of the radiator. Pull the plug & short the circuits to test the fan. With the key on, jump the ground wire to each trigger wire in turn. I'm pretty sure it's a brown ground wire and black low speed wire. High speed is brown to black/red IIRC. Each circuit is controlled by a relay and separately fused as well.

jdirty · « **Reply #6 on:** October 08, 2011, 08:48:13 PM »

when i pulled the plug the plastic crumbled to bits and i'm not so sure with the arrangment of the wires. i didnnotice though that throughout the radiator, the temp was avg 85-90. upper rad hose was 154 nearest to tstat housing and lower rad hose was 126 ish nearest to housin. upper timing case cover was around 150. i did try the paper test on the fan clutch and it stopped. and the two
hoses that were supposed to go to the heater core, cold. i grasped and didn't feel anything.

DesktopDave · « **Reply #7 on:** October 09, 2011, 10:52:28 AM »

It's hard to see here (looking at the rear of the plug) the green ground wire is in the lower center, the black/red wire is on the left and the solid black wire is on the right.

I'm confused by your fan clutch test. When hot it should easily shred newspaper and not stop. It should only stop easily when it's cold. The heater hoses should be hot if the valve is open & the heater fan has been on for a little while.

jdirty · « **Reply #8 on:** October 09, 2011, 05:50:32 PM »

wow thanks!! i've been looking for a photo. lol

i am confused with the test i did as well. because i didn't use a newspaper. i used a two sheets of 8x11 paper folded into 1/2 then into 4. so i guess into a 1/8th of the original size. i found it really odd that i was able to stop the fan clutch.
last night a friend of mine who recently changed his fan clutch on his e30 and his brother's e36 stopped by and he said that no, mine wasn't spinning freely while as compared to as the two broke fan clutches that he recently replaced. he said his fan clutch could be spun freely with a finger while the engine was off. as compared to mine that had resistance at least. i was just wondering what was going in because when the temp is high the fan clutch should engage and shred stuff.. so if it was stopped with my measly folded paper.. it's either it's broke or i'm not getting an accurate reading in my cluster..

which made me think of taking out the cluster and checking the backside..

but the temps i listed though.. is that even normal?

the two hoses that i was referring that's near the heater core.. i bypassed the heater core and looped them together.

DesktopDave · « **Reply #9 on:** October 09, 2011, 06:28:03 PM »

Those temps don't seem abnormal to me, if the fan clutch is shot. If the fluid leaked out past the seal it's worthless. That's probably the only thing that's wrong.

Your looped hoses look like a fine plan to me, except in the winter...

jdirty · « **Reply #10 on:** October 09, 2011, 06:57:31 PM »

i actually got this idea from the original owner. i bought the car and the lines were already looped. survived a winter with the hoses like this since the original heater core was busted. but what i don't get is.. why are those looped hoses cold? (i meant to draw two hoses that make up the red line)

are those two hoses cold because they really are? and i'm just expecting them to be hot like the passenger side rad hose because my temp gauge tells me so?

you mean that if i'm getting those temps on the rad hoses and the thermo housing.. chances are my fan clutch is dead?

jdirty · « **Reply #11 on:** October 10, 2011, 12:34:29 AM »

checked the cluster, pulled it out and tightened the nuts at the back. took the car for a spin. temp didn't go up right away during idle but as soon as i ran the car it quickly rose to 3/4. parked the car again since i was just running around the apartment complex parking lots.. out of curiosity i felt like touching the lower rad hose. cold. upper rad hose, bad idea it was pretty hot.

seems like a faulty thermostat that acts up whenever and get's stuck closed.
would this:

explain the heater core hoses being cold and when they were plugged in no hot air was coming from the heater at full blast?
would this also cause the fan clutch to not engage since i could stop it somehow with folded paper?
am i cursed with a phantom air bubble? lol

and thanks for always taking the time to reply Dave and anybody else who wants to contribute to this hunt.

DesktopDave · « **Reply #12 on:** October 10, 2011, 07:27:57 AM »

I'd replace the fan clutch first. It's definitely bad. I have a few around I'll let you have for cheap.

jdirty · « **Reply #13 on:** October 10, 2011, 03:39:14 PM »

i'll try replacing the thermostat with an unopened spare that i have here since i'm quite broke. lol i'll keep your offer in mind since replacing the fan clutch is inevitable. unless i thrash it altogether with the aux fan and do the volvo electric fan... sounds like a hassle though

DesktopDave · « **Reply #14 on:** October 10, 2011, 04:01:36 PM »

The fan update is pretty cheap. You don't need a Volvo fan especially, it just bolts up pretty well in the available space. Anything with a two-speed fan and large enough frame would work out well.