Yet another question: overheating

[Mr. BILL]

OK, I assure ya'll I'm as tired of asking as much as ya'll are reading them, but here goes. As winfred suggested, the TPS "woke up" and the car will start and idle fine.

After a few minutes, the temp comes up, but heads tword 3/4. I have bled it twice. (BTW, this is a M20 engine). I'm thinking that it's not trapped air because when I drive it, the temp doesn't come back down.

I noticed that the crossover pipe and the hoses at each end are cool to the touch, even after the temp has gotten to 3/4. I'm wondering if I may have put the T-stat in backwards. :(

I sure hope not, because one of the screws that hold the cover on was replaced by a screw & nut as the hole stripped out (previuos owner). Of course, this is the one that would be nearly impossible to remove without taking the whole housing off, which may include taking the intake off again :p

So, if you will, please indulge me again and offer suggestions. Does it sound like air or a backwards T-stat, or something else?

[632 Regal]

sounds like air, if you want to check the t-stat I think you can see it if you pull the hose and then for sure youll have air and can re-bleed it.

[Mr. BILL]

Thanks Jeff, I think I'll try the "blow into the radiator" method. I was thinking about removing the hose on top of the housing and look in to see what's the deal. If I look into the housing side, I should see the spring, not the "pyramid" right?

[winfred]

the small disc and spring goes in, drill a 1/8" hole at the arrow in the thermostat to avoid the bleeding problems

[Mr. BILL]

Thanks Jeff, I think I'll try the "blow into the radiator" method. I was thinking about removing the hose on top of the housing and look in to see what's the deal. If I look into the housing side, I should see the spring, not the "pyramid" right?

[Mr. BILL]

OOPS, double post

[Mr. BILL]

I checked, and the disk is in the housing, facing the engine. The little "pyramid" is in the cover. So, it seems as though I have it in there properly and I took your advice about drilling a hole from an earlier post of yours. However, the hose that runs from the t-stat cover, to the crossover pipe, to the hose that goes into the lower radiator remains cool to the touch.

Seems to me that the t-stat isn't opening allowing coolant to flow thru to the radiator. Could air cause this? The only other thing I can think of is, does it matter if I got the connections switched on the two sensors on the housing. I forgot to mark those when I disconnected them. Maybe I have them reversed.

I sure appreciate your taking the time to help! If you ever have any questions about furniture, I'm you man.

[winfred]

if it's purged of air ether the thermostat is not opening or the radiator is clogged if the right side of the radiator never gets warm, i've seen it both ways, the plugs on the temp sensors are color coded blue and brown, sometimes one of the sensors gets replaced with a black one, the other should still match it's sensor, wire length will also suggest which is which

[632 Regal]

I'm not sure as i have the V8 how your hoses run at the thermostat area.

[Mr. BILL]

I have the blue connected to the front sensor. I suspected the thermostat not opening. So, I loosened the hose that comes from the cover and coolant spilled out. So I guess it's working.

I checked the coolant itself and it's weak. Only to 10* freeze level. Could that cause it?

[winfred]

more water generally cools better, sensors won't make it overheat, just run bad or read wrong. lower hose/xover pipe should at least get warm


I have the blue connected to the front sensor. I suspected the thermostat not opening. So, I loosened the hose that comes from the cover and coolant spilled out. So I guess it's working.

I checked the coolant itself and it's weak. Only to 10* freeze level. Could that cause it?

[632 Regal]

I suspected the thermostat not opening. So, I loosened the hose that comes from the cover and coolant spilled out. So I guess it's working.

Nope, water will pour out even if it was in wrong, remember that hole you drilled? You have to really make sure that thing is in there correctly before you can go any further. It "could" be air but if its the thermo in backwards you will never purge the air and you will never get the thermo to open, nice way to crack a head man.

[Mr. BILL]

Jeff, I visually confirmed that the t-stat is installed properly. I sure appreciate ya'll helping me sort this out. At this point, I'm suspecting a bad "new" t-stat.

[632 Regal]

if it was it should have had a check ball sort of bleed on it. Throw it in a pot of boiling water to confirm operation.

[winfred]

ditto on the boiling water, i keep a pint paint can to heat with a torch handy for testing

[Mr. BILL]

No, it's not a BMW, it's a Whaller. Since my last post, I removed the T-stat and tested it in hot water, it works. So I'm eliminating the thermostat as a culprit. I also decided to start over.

So I drained the system and flushed the bejesus out of it. I flushed, back flushed and flushed some more until only clear water came out of the radiator and the t-stat housing. There was some chalky crap that came out at first.

Then, I followed the Bently fill instructions to the letter. This time, I was able to open the bleeder on the t-stat cover. I filled the system and started it up. When the temp came up, I opened the bleeder on the radiator. Very little came out, and yes, I filled the system before starting it up. The car idled for 6-7 minutes and the temp stayed straight up, normal. So I decided to take it for a spin. I didn't go 200 yds when the temp started to head toward 3/4. Damn!

I opened the valve and nothing came out. So, I took off the rad cap, it was at about the cold mark. So, I guess I'll try again tomorrow. It's 1:30 Am, I'm sure my neighbors think I should call it a night.

Thanks again for trying to help me sort this out.

[ryan roopnarine]

sounds like what happened when my water pump came off its impeller. we took the thermostat out, bled it....would hold steady at idle but start to heat up when driven. was that changed recently?



No, it's not a BMW, it's a Whaller. Since my last post, I removed the T-stat and tested it in hot water, it works. So I'm eliminating the thermostat as a culprit. I also decided to start over.

So I drained the system and flushed the bejesus out of it. I flushed, back flushed and flushed some more until only clear water came out of the radiator and the t-stat housing. There was some chalky crap that came out at first.

Then, I followed the Bently fill instructions to the letter. This time, I was able to open the bleeder on the t-stat cover. I filled the system and started it up. When the temp came up, I opened the bleeder on the radiator. Very little came out, and yes, I filled the system before starting it up. The car idled for 6-7 minutes and the temp stayed straight up, normal. So I decided to take it for a spin. I didn't go 200 yds when the temp started to head toward 3/4. Damn!

I opened the valve and nothing came out. So, I took off the rad cap, it was at about the cold mark. So, I guess I'll try again tomorrow. It's 1:30 Am, I'm sure my neighbors think I should call it a night.

Thanks again for trying to help me sort this out.

[Mr. BILL]

Jeff, It's a Whaller t-stat amd I took it out and put it in a pan of hot water, it works fine. So I'm eliminating the thermostat as a cause.

I decided to start over, so I disconnected all hoses and flushed the bejesus out of the block and radiator. When I back flushed the radiator, some chalky/milky water came out. I flushed and flushed until it was clear. Then I flushed some more.

I put it all back together and filled it up following Bentley's instructions to the letter. It ran cool for 6-7 minutes at idle, so I took it for a spin. I hadn't gone 200 yds when the temp started heading toward 3/4. Since it was 1:00 AM, I decided to call it a night, er morning.

This morning, I topped off the tank until coolant ran out the bleeder on the radiator. BTW, I got the bleeder on the t-stat cover to work also and used it as well. Anyway, I started it up and let it idle for 6-7 minutes. There was very little air this time, so I took it for a spin. I was able to go around the block twice before the temp headed to 3/4.

Before I shut it off, I opened the bleeder on the radiator and no bubbles, just a steady stream of coolant. I reved the engine and still no bubbles and the heater is working, blowing very warm air. So, I'm thinkiing no trapped air.

So, now I'm thinking either the radiator is bad, or I was sold the wrong head. It's supposed to be from an '89 325 and I was assured it was a match. I compared them side be side from all angles before installation and from what can be seen, they are identical, so I don't know.

I'm frustrated, but, I really appreciate you and winfred helping me sort this out.

[winfred]

sounds like the white chalky crap may of killed the radiator, 87 and up 325I m20 is exactly the same head, 88 super E is the same casting, rockers/shafts and valves but single springs and a wussy cam

[Mr. BILL]

it's a whaller and I tested it in a pan of hot water.