89 325i cooling issue...

I am having a cooling issue with my 89 325i and am looking for ideas. I removed the thermostat yesterday to rule it out. I believe I am either looking at a plugged radiator or a faulty water pump. I am
pretty sure the system is well bled so that isn't the issue.
The problem has came on slowly and not all at once. I am running well over normal temp at various times. The car also gets warm very quickly when it's first started up. All of this is reading on the guage and I haven't actually lost any coolant due to overheating. Is there a way to actually check the water pump? I thought about running some radiator flush through the system but I'm not sure it would do any good. How do I go about diagnosing this without throwing parts at the problem?
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take the hoses off the heater core and turn it over or start it for just a second... you'll quickly see if it's pumping coolant around. also check and make sure your fan clutch works... warm the car up to mid-range on the temp gauge and get a pencil or small stick or something and stick it in the fan blades... they should not slow down or stop... if they do then you need a fan clutch. in my e30 the a/c doesn't work so I just took the compressor belt off and hit the a/c button... this will make the secondary electric fan run which will help cool the engine.
good luck!
Psycho wrote:

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snipped-for-privacy@gmail.com wrote:

The fan clutch will not cause the engine to overheat "quickly" as the OP wrote. It will also only allow the engine to overheat when the car is driving very slowly or stationary. Any time it is moving it will have enough air flow to keep it cool.
--
-Fred W

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On Mon, 30 Oct 2006 07:36:17 -0500, Fred W wrote:

I disagree. My fan clutch went in the summer time, and it affected temperature while driving, as well as the usual stop/go traffice thing.
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no one wrote:

Then the fan clutch was not the only problem.
--
-Fred W

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Psycho wrote:

Unless you have some serious goo in the cooling system (you haven't been running that Prestone crap have you?) in all liklelyhood the problem is the water pump. The only other explanation would be the radiator is blocked with crud.
Buy a waterpump (pretty cheap on E30's). When you drain the engine to replace the pump, backflush the radiator with a garden hose. Just pull both the big coolant hoses from the radiator off the engine side and direct your garden hose into the bottom one, letting the water flow out the top one. I usually seal the garden hose in with a rag wrapped around it.
Put (good) new coolant in.
--
-Fred W

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On Mon, 30 Oct 2006 07:41:49 -0500, Fred W

This is pretty much what I'm thinking at this point. I'll flush the radiator and hope that solves the problem. I'll check the water pump as the other person suggested as well. It can't hurt, right?

Is there actually a real issue with Prestone? The coolant is actually quite clean although I'm not sure what brand it is. Heater works very well so I suspect I've got a blockage... Sucks to be me...
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Well, here's the diagnosis so far. Water pump replaced, impeller on old pump had 1/4 inch gap between pump and housing compared to new pump. Obviously, they don't work very well when the water just swirls back around the impeller. Radiator flows water through it very well. Flushed all of the old coolant out and didn't see anything unusual.Will have a better idea tomorrow if the problem has gone away...

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Final diagnosis of this problem. Running down the road today, the car stays very cool however as soon as I start sitting still, the temp starts to climb. I popped the hood and stuck a pen into the fan only to find that the clutch has gone bad. I'm a bit annoyed as the damn thing is about six months old (replaced it once before due to overheating issues an d the problem partially went away). Looks as though I'll either be fusing the clutch to make it a continuous fan or I'll be replacing it with an electric unit. The electric is the better choice as it takes less in the form of horsepower to operate.

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I won't say that your fan clutch hasn't gone bad again, but don't forget that you already have a 2-speed electric fan on the E30. And it should be seeing some action if your temperatures are climbing above 90 C.
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As of the other day, it was coming on but it's not enough to keep the temp down. I'll remember to check it again when I go back outside.
On Wed, 1 Nov 2006 22:49:15 -0500, "Bob Smitter"

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Psycho wrote:

Well, you seem to have had more than one problem, eh? The overheating is gone now except when at a standstill.
I would try fusing the clutch somehow myself. The amount of horsepower consumed by the fan is not all that much, especially when moving along briskly and getting good airflow through the radiator. Also, even an electric fan will consume horsepower through the alternator. Plus the added load on the alternator may cause that to fail more often, and the aftermarket electric fan motor may crap out some day. I prefer things simple and mechanical, myself. YMMV...
--
-Fred W

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Well, another thought on this. Fusing the fan MAY cause it to loosen and possible spin off into the radiator when the engine is shut off. After having this thought, and the fact that my first attemp at fusing the fan didn't work, I decided to go electric. Damn difficult to find a fan that will fit between the radiator and the motor. Not much room there at all. Having mixed results at cooling as the thermostat switch I got doesn't seem to be very effective. When wired to come on with the key, I still slowly heat up to an undesired temperature. Might be because I don't have a thermostat installed at the moment or possibly even an air bubble in the system still. The aux fan seems to have a bad thermo switch so it's no help either. Why does this have to be such a pain in the ass???
On Thu, 02 Nov 2006 14:49:15 -0500, Fred W

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