engine and drivetrain Cooling Issues

[Mike Self]

1. Harbor Freight has a no-contact temp sensor with a laser pointer built in on sale for $26 or so...regularly $59.

2. If you talk to a local radiator shop about recoring a stock 02 radiator with a three row core, a RADAC 25 core is the one they used on mine some years ago. The part number may have changed, but I think it's still available.

But you shouldn't be having problems with an engine in a mild state of tune unless the current radiator is really clogged up or there's something else causing the problem.

First thing I'd do is make sure you actually have a problem--even a hand-held pocket temp gauge will give you a reasonably accurate reading at the top of the radiator tank, which is where the coolant is the hottest, having just been pumped from inside the engine and right by the temp gauge sender...

cheers

mike

[SkidMarc]

Mike,

Thanks for the input.

I'm going to a shop that I've used before to get the radiator recored (hopefully). I'll pass along your recommendations. While out running errands, I will be picking up a temp sensor (and a couple other bits) from Harbor Freight.

After burping the system again yesterday, there was some improvement for a while. When I got home, it was running hot and boiling over a bit. There's definately a problem.

Cheers,

Marc

[c.d.iesel]

.....so what makes you think that the head gasket in this

motor isn't leaking compression into the cooling system ?

another cooling system tester will tell you if gasses

are mixing with coolent - test chemical changes color

when tester is in place instead of radiator cap.

otherwise you have been suffering from a bad radiator all

this time

[SkidMarc]

That could certainly be the problem. Could you direct me to the products that could test that?

Update:

I got a bit of sticker shock when the radiator shop informed me that it would be $450 to recore my unit. While, the new construction would be far more efficient, it's a lot more than I want/expected to pay. I'm going to do some more checking around.

In the meanwhile, I'm going to install a new water pump and thermostat (thanks Blunt) and test with my old (auto) radiator. At least at that point, I would have eliminated a couple possibilities.

Stay tuned.....

Marc

[Swiftus]

Hey Marc,

Sorry about the late response. Distilled water should be the only kind of water used in a coolant system. Ever. All of the extra minerals and crud in basic tap water can either collect in your coolant system, or worse, instigate reactions between the various types of metals in the engine... ie aluminum head and iron block...

I had a similar quote when I wanted to get my Opel's radiator re-cored. Happily, I found that a Honda Civic's radiator was a good fit and the right price ($60 shipped brand new).

I think that the e21 radiator is a bolt in replacement (I believe that is what Clay has on his car), all you need is different bolts.

Let us all know how it goes.

Jay

[Lee]

Mark

For $250 you can get an OEM e21 alu-core/plastic tanks radiator. These are highly efficient and offer tons of clearance with your water pump. Don't fool around, call Blunt.

Behr and Nissan make them.

[SkidMarc]

BTW,

I picked up the IR temperature gun from Harbor Freight yesterday evening. Let me know if any of you guys in the D.C. "crew" (or in the area) need it.

Marc

[M3M3]

I do have an extra used e21 radiator. worked fine when I took the car apart. email me if you want to buy (cheap!).

[SkidMarc]

Thanks for the offer for the radiator. I'll keep that in mind.

Update:

Replaced the water pump and thermostat (75C). The gauge still shows warm running (just up to the RED). Put the gun on various parts of the motor here are the readings:

Top Hose (to radiator) 175F

Valve Cover 190F

Thermostat (70C) - this could be the problem as it may not reach actuating temps.

Headers: 395F

Hose (from Thermostat): 141F

Ambient temps here today in the D.C. area were 80F w/ low humidity. Schweet!

I'm thinking that the gauge is off. The old light bulb in series must have had a purpose. Given that the thermostat isn't reaching operating temperature, I'm given to believe that it's not allowing enough flow to cool properly. I may order a 70C piece.

Also, if I let the car idele for an extended period of time, the temperature gauge shows a reduction in temperature - back to middle (the IRunit confirms this). This would point to the thermostat?

Anyone care to comment?

Thanks for your support. Greatly appreciated!

Marc

[Swiftus]

Definitely sounds like a lack of flow issue.

Here's one, try running without the t-stat at all. See if that cools the temp down.

That light bulb is making me squeamish though. It shouldn't be there and its futzing with the gauge.

Make sure that your temperature readings are as soon as possible after a 'hot' episode. That will help you get a better idea of what the correlation is between the gauge indication and the coolant temps.

Also, just thinking out loud here, isn't the temp sender after the t-stat? Wait, it may be just before. I don't want to go out to the garage and look.

Whatever the case, you can always try no t-stat or just a flow-restrictor (fancy-pants washer). If its good enough for a race car it good enough for me!

[yeewiz]

Put the gun on various parts of the motor here are the readings:

Top Hose (to radiator) 175F

Valve Cover 190F

Thermostat (70C) - this could be the problem as it may not reach actuating temps.

Headers: 395F

Hose (from Thermostat): 141F

FWIW, check this thread for my IR gun readings:

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,323234/highlight,/

HTH!

[SkidMarc]

Jay,

It would seem that great minds think alike. I've been considering gutting out one of my "suspect" thermostats to see what happens. I may give it a shot tomorrow. Also, the light bulb was employed on my old engine. I removed it before installing the "new" motor. It was originally wrapped in electrical tape.

Wiz,

Thanks for the numbers. Mine are somewhat close to yours. However, I'm running a Stahl-type header and iriduim plugs which may contribute to warmer running. BTW, my gauges are grounded. I was forced to do so when they were bouncing wildly about last year.

Keep those cards and letters coming!

Marc

[SkidMarc]

OK Boys & Girls,

Got up early this morning and checked the car over. Topped offer the radiator (will monitor). No leaks. Car started promptly (as usual) and I took it for an extended drive around the neighborhood.

Temperature (gauge) remained steady for the forst 10 minutes of the drive (longer than usual - though it was a bit cooler then usual) before gradually moving up. Tops off at the RED another 10 minutes later. I didn't notice any change in performance or signs of running hot. Continued to drive another 10 minutes - still no change.

Got it home and put the gun on it. Readings were similar to yesterday with the thermostat temp at 75C, head @ 185F, Headers @ 395F, top of radiator 210F, top hose @ 175F, Block @ 191F, Bottom hose @ 118F. Do these sound normal?

I'm starting to believe that it's the gauge. I'm going to take it into work to see how it fairs. Wish me luck!

[M3M3]

gauge or sender. check ground on gauge and test sender with ohmeter and thermometer.

[SkidMarc]

Thanks Marshall. How do I use an ohm meter to check the sender? BTW, I still may get that radiator from you.

Can anyone confirm that the engine is running within normal temps?

I pulled the (iridium) plugs this morning and they were nearly white. #4 looked more like normal though. I tried swapping in the original plugs but they ran like crap (unusable).

What I believe I need is someone that can really tune these things - timing, mixture, etc. Anyone?

In the meanwhile, I'm going to try to source some standard NGKs and learn to (properly) use a timing light.

-M.