another overheating thread

[boarder2k7]

I have not read this thread so sorry if this has been covered. The stock E36 two speed auxiliary fan can be tested as follows :

http://www.nmia.com/~dgnrg/page_20.htm

And the double temp switch can be tested by mildly overheating the engine (2 needles width to the right of optemp, which is 12 oclock on the gauge) by blocking the radiator and grills with a large board and running the engine at idle. Once it reaches that test temp, shut the engine down, then immediately key2 the ignition. Goto the front of the car and you should be able to hear the fan running at high speed. After some time, it should switch down to low speed, and then switch off a short while later.

Comes into thread with attitude of "tl;dr" and immediately recommends deliberately overheating an engine known to warp heads as a diagnostic step.

Let's see... join date... 10 days old. Ahh, I see we're off to a good start, 17s gonna 17.

This is just all bad form dude, I hope you haven't been doing this with your other posts.

[Richard81]

Comes into thread with attitude of "tl;dr"

I believe I started off with an apology for not reading through the thread, but wanted to contribute information with MAY be useful to the OP. Lets remember this thread is primarily about the OP and not you. Can you recognise good manners when you see it ?

and immediately recommends deliberately overheating an engine known to warp heads as a diagnostic step.

I'm sorry but are you driving BMWs ? The same engine that has a 3% leakdown after 198,000 miles ?

https://www.bimmerforums.com/forum/s...starting-issue

Read Michael Bruno's posts. Extrapolate from that. And that is 20 yr old metal alloy technology.

We are not talking toyotas here and the engine is not made of plastic. It can comfortably survive a mild overheat, which is what I recommended. Its not even an issue. I'm surprised this is not understood.

I even stated exactly what I meant by a mild overheat so there's zero doubt even in the minds of newbies. Please do read my post more carefully.

Let's see... join date... 10 days old. Ahh, I see we're off to a good start, 17s gonna 17.

Clearly, join dates and post counts do not correspond to in depth knowledge about the car.

[Richard81]

Ok, so I decided to read this thread. These are my comments, and they were clear pretty much within 3 posts.

a. The thermostat and water pump are not the problem. In any case this can be very easily tested. Touch the upper and lower rad hoses after the engine has reached optemp. They should be hot. There's no need to test further because the chance that this is the problem here is SO low to begin with. So this takes what 5-10 minutes engine running time and 20 seconds 'hand' time to figure out.

b. The thermostat cannot be the issue because you are not overheating or running hot and that is also almost never the issue in such cases. Also shows that the wp is fine.

c. Someone suggested checking the wiring and fan, which proved that the wiring, relays, and the fan's two speed running is not the problem. This is the very first thing that should have been done here. A seasoned person can do this within 5 minutes, a newbie may take like 15-30 if its his first time.

The OP is clearly seasoned. So total diagnostic time so far would be about 10 minutes for the OP. And this includes a imo needless step (a). But can be done for thoroughness.

This was the radiator's double temp switch all along. And once the wiring and fan are tested, it is confirmed that it is the double temperature switch. Nothing else can be wrong.

We've all had the unfortunate experience of buying a new oem product that failed in a matter of weeks and months. It should not be unthinkable. And the OP's symtoms show that clearly.

In a situation like this, the first thing to check is wiring, fuses, the relay and the fan's two speeds. If that is ok, then the problem is the double temperature switch/ the equivalent in aftermarket radiators. Simple. So it appears my first post in this thread was indeed relevant. Though I posted it without reading anything here before that.

This problem need not have taken 3 months to nail down. It could have taken like 10 minutes for the OP. For a noob it would have taken 30 minutes after maybe an hour of study/youtube watching.


p.s. There is no need nor has there been any need to jack up or otherwise raise the front of the car to bleed it. Modern BMW engine have a bicavity cylinder head. It has become so simple because BMW redesigned their cylinder heads and cooling systems to better avoid the air and temp problems of the old setup. For anyone interested there's an in depth discussion about this here :

https://www.bimmerforums.com/forum/s...ks-overheating

[Nanniepoo]

I'm sorry but are you driving BMWs ? The same engine that has a 3% leakdown after 198,000 miles ?

https://www.bimmerforums.com/forum/s...starting-issue

Read Michael Bruno's posts. Extrapolate from that. And that is 20 yr old metal alloy technology.

We are not talking toyotas here and the engine is not made of plastic. It can comfortably survive a mild overheat, which is what I recommended. Its not even an issue. I'm surprised this is not understood.

I even stated exactly what I meant by a mild overheat so there's zero doubt even in the minds of newbies. Please do read my post more carefully.




Clearly, join dates and post counts do not correspond to in depth knowledge about the car.

Ugh. I don't want to turn another thread into a shit show. But please explain how one would extrapolate anything from ONE DATA POINT.


While I think that people do think these engines are too fragile when it comes to an overheat, I still would recommend testing that switch in hot water as opposed to purposely overheating your engine.

[Richard81]

Ugh. I don't want to turn another thread into a shit show. But please explain how one would extrapolate anything from ONE DATA POINT.

It depends on the nature of that data point. I don't want to deviate from the OP's topic here. Strip out this argument into a new thread and I will explain in the context of my earlier commentary.

While I think that people do think these engines are too fragile when it comes to an overheat, I still would recommend testing that switch in hot water as opposed to purposely overheating your engine.

If you have great confidence in your knowledge of the engine, and if you word your posts comprehensively, you will make 10 minute easy peasy directives instead of those that take noobs 30-60 minutes and alot of trouble.

The problem with you is that you frequently forget your audience. You are not writing for experts. You are writing for motivated noobs. That's why my posts are long - I put alot of background information so a motivated noob will learn things in depth. Yet I frequently also tell them to to google this, youtube that, download this, etc so that the idiots who can't really be bothered are not fully spoonfed, and weeded out that way.

[BMWe36AS]

the only reason it has taken 3 months to diagnose this is because it's winter and it's not as severe. but it's been warmer weather out so I'm back at it as the symptoms show up quicker and more often.

so back to everything being ok except the dual temp sensor. so the old one died I bought a brand new one and that one's dead too? what r the chances of that?

also still no input on what the temp at the head is in relation to the temp at the rad? like if my Guage shows 210 at the head what is it at the rad?

[shogun]

To check temperatures I have a small non-contact infrared thermometer with pointer, costs less than 20 bucks, or check in your kitchen, often these things are also used for cooking.
I use that quite often for the car, not only for the cooling system but also for example to check brake disc temps = easy to spot a different temp on one brake by sticking calipers, etc.