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gruizer

Stupid Cooling System Has Me Pulling My Hair Out!

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Ok guys, I'm getting to the end of my rope here. I bought a 68 1600 a few weeks ago. The previous owner(s) put a 1974 2002 engine and an upgraged 320i radiator with new 5 blade fan.

I've noticed that the car started to get hot whenever I would get on the freeway, and since the car has a 5-speed out of a 318i, the RPM's wouldn't really get past 3500. The temp gauge would climb up to the 3/4 mark for about two weeks. Then the other day the guage would climb whether I was around town or on the freeway. Here's what I've done to try to fix the issue:

1. Replaced the thermostat with a new one (Whaler), made sure it worked in a pot of water first.

2. Pulled the radiator and flushed it with the garden hose from the bottom to make sure water came out the top.

3. Pulled the waterpump and checked the insides (looked brand new and spun freely)

4. Drained the block of all the green fluid. and ran straight water till only clear water came out of the block.

5. Put it all back together with and filled it with the blue BMW coolant mixed 70/30 water to coolant.

5. Ran it with the front end jacked up and squeezed the bottom hose with the heater on and the radiator cap off.

The temp guage gradually made it's way all the way to the red. I used an infared gun to measure the heat at both the top hose and the valve cover and neither showed temperture above 120 deg F.

What am I missing?

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Guest Anonymous

it might be just a guage problem, not overheating at all. See if the guage climbs as you turn on other things. If so, clean up your grounds.

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Also check your timing. Small adjustments can also make a difference in the cooling of the motor. I am running into the same problems and think I am 1 tooth off on my distributor & that is causing me difficulties in timing it correctly. I have the traditional 1600 set up & have gone through all the same steps. Still does the same thing. So try your timing, may have something to do with it!

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Thanks for all the replies!

Bill.in.mont - The guage does spike ever so slightly when I turn the lights on, but that's it. How do you clean up the grounds? Do I need to pull the guage out and clean it in the back? I cleaned the connection at the sender end (by the fuel pump).

allbim - I will try pointing the IR thermometer at the sending unit. The wikipedia thing went way over my head.

jscaptura1 - Is adjusting the timing as easy as loosening the distributor hold down and turning to advance or retartd? Any suggestions on doing this without a timing gun?

mlytle - The upgraded radiator is about a year old. The previous owner had to replace it because the fan ate the radiator. I changed out the motor mounts to prevent that from happening again. Yes I can see coolant trickling into the radiator from the top hose, but that hose doesn't really seem to expand very much. It's almost as if it doesen't really look like it's moving alot of coolant through there. Is that normal?

mossyboy6 - Yes the heater blows hot, am I supposed to run the fan as well or just have the set to heat? I will try to burp it again when I go home for lunch today.

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If you want a second set of eyes to have a peek at the grounds and the cooling system, I'm in Livermore. You can drop me an email using the button above.

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You just need to turn it to hot, you don't need the fan on to burp it.

Make sure the valve opens when you do.

Jack her way up and fill her to the top, then let her burp for about 10 min.

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Thank you, thank you CJ. Email sent!

mossyboy6, thanks for the reply. I'll get to massaging in a few minutes.

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Thanks for all the replies!

mlytle - The upgraded radiator is about a year old. The previous owner had to replace it because the fan ate the radiator. I changed out the motor mounts to prevent that from happening again. Yes I can see coolant trickling into the radiator from the top hose, but that hose doesn't really seem to expand very much. It's almost as if it doesen't really look like it's moving alot of coolant through there. Is that normal?

yes, you should see significant flow in there as it gets warmed up and the tstat opens.

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I used an infared gun to measure the {temp} at both the top hose and the valve cover and neither showed temperture above 120 deg F.

You''re not getting cooling circulation in the radiator. Shoot it at the intermediate recirculation hoses that attach the t- stat to the coolant neck. If they''re hot, (180+) the thermostat''s sticking. If they''re cold, SOMETHING is preventing water from flowing through the block, and thus opening the thermostat. Also, do you get a nice, hot heater output? Yes tends to mean t-stat or radiator, No points to coolant circulation. Or a stuck heater valve or flaps. The IR gun will solve this, if you work at it methodically. t')

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Guest Anonymous
Thanks for all the replies!

Bill.in.mont - The guage does spike ever so slightly when I turn the lights on, but that's it. How do you clean up the grounds? Do I need to pull the guage out and clean it in the back? I cleaned the connection at the sender end (by the fuel pump).

If you only get a bit of movement when you go from nothing on to everything on then don't worry about it. But if turning everything on moves the needle into the red, start by cleaning the two grounds from the battery and continue by cleaning any brown wires where they attach to the body.

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Thanks for all the helpful suggestions. Bill, I was pretty sure that I didn't have connection issue. Low and behold, I cleaned every ground that I could find and even ran a wire between the two lugs behind the gauges and then a wire to a seperate ground. It totally fixed it. The guage now tops out at just a tad over half way and it also fixed my jumpy fuel gauge issue!

Chris (CJ) looked over my car and pointed out some things to fix. I also had the chance to drool over his Fjord 2002. Thanks man, I owe you big time.

You guys are awesome.

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