Valley pan and coolant pipes O-ring life

[fmugur]

I might be wrong but I thing the life of the valley pan and the coolant pipes O-rings in the back of the engine (M62) can have a longer life if the coolant circulates through the engine after it's shut off.

Last year I had the engine out of the car and I replaced all the gaskets, O-rings... everything. When I did that I found that the two O-rings on the coolant pipes at the back of the engine were squared and harder rubber than the front or a new set. The interesting part was that these O-rings have been replaced a year and a half before that when I did the valley pan. There was no coolant leak from these O-rings last year but I assumed it was coming.

This year I had the tranny out for a rebuilt and I found a coolant leak which it was coming from one of the O-rings. I don't remember if the big or the small one but both looked square and hard. The front o-rings looked good and soft.

I replaced them again and I suspect the cause of this is the heat that builds up after the engine shuts off or it can very well be because there is less ventilation during normal operation behind the engine.

Now, one solution I am thinking of is to have the auxiliary water pump running a few minutes after the engine shuts off. To accomplish this you can use the REST button or code the car to turn that option on if that's an option with NCS Expert. I am not sure for controllers that have MAX instead of REST.

I will also try civdiv solution to lower the engine temperature which will also help for this problem.

Any thoughts?

[SlickGT1]

Yea you should deff do the civdiv upgrade. I can't see it hurting anything. The rest feature is also a good idea.

Now, I am not sure this is your problem. I mean think about it, the original o ring lasted how long? 9 years about. Are you sure that the same new o ring failed again?

[diyanich]

To me,it's the quality of the O-ring that would matter.
Could be as easy as a crappier compound used to make it and that shortens it's life.

Originally Posted by fmugur

I might be wrong but I thing the life of the valley pan and the coolant pipes O-rings in the back of the engine (M62) can have a longer life if the coolant circulates through the engine after it's shut off.

Last year I had the engine out of the car and I replaced all the gaskets, O-rings... everything. When I did that I found that the two O-rings on the coolant pipes at the back of the engine were squared and harder rubber than the front or a new set. The interesting part was that these O-rings have been replaced a year and a half before that when I did the valley pan. There was no coolant leak from these O-rings last year but I assumed it was coming.

This year I had the tranny out for a rebuilt and I found a coolant leak which it was coming from one of the O-rings. I don't remember if the big or the small one but both looked square and hard. The front o-rings looked good and soft.

I replaced them again and I suspect the cause of this is the heat that builds up after the engine shuts off or it can very well be because there is less ventilation during normal operation behind the engine.

Now, one solution I am thinking of is to have the auxiliary water pump running a few minutes after the engine shuts off. To accomplish this you can use the REST button or code the car to turn that option on if that's an option with NCS Expert. I am not sure for controllers that have MAX instead of REST.

I will also try civdiv solution to lower the engine temperature which will also help for this problem.

Any thoughts?

[fmugur]

Originally Posted by diyanich

To me,it's the quality of the O-ring that would matter.
Could be as easy as a crappier compound used to make it and that shortens it's life.

I used bmw parts though...

[fmugur]

Originally Posted by SlickGT1

Yea you should deff do the civdiv upgrade. I can't see it hurting anything. The rest feature is also a good idea.

Now, I am not sure this is your problem. I mean think about it, the original o ring lasted how long? 9 years about. Are you sure that the same new o ring failed again?

I know, I thought the same same thing but I don't think I have seen people describing the conditions of the o rings when they took them out. I guess these are changed when you take all apart to do the valley pan since you are in there. I don't know what part of the valley pan was failing either. I am guessing the part that is closer to the firewall but these are only speculations based on my findings. I can be wrong but why two of them "cooked" only on that side? What else can cause that?

[diyanich]

When I removed old O-rings from back and WP housing as well,all 4 were squared,but also they were disintegrating the way if the top layers were slowly peeled off.Hard to describe,but there was a lot of rubber flake alike stuff yet attached to the O-rings.
I would this that the answers to your question would be:
1. Since those pipes aren't bolted in any way to the engine,any excessive vibration would make them slide inside while it's cold.
2. Aluminum oxidizes and gets rougher,so the contacting surface is becoming like a fine rounded file,apply the above mentioned condition #1 and here you have a failure in no time.

When I did VP I also opted for new pipes,although the old ones were yet looking like a good clean up would bring them to an almost "new" condition.
But I think it's not easy to restore a machined surface to it's original condition once it was all corroded.

Originally Posted by fmugur

I know, I thought the same same thing but I don't think I have seen people describing the conditions of the o rings when they took them out. I guess these are changed when you take all apart to do the valley pan since you are in there. I don't know what part of the valley pan was failing either. I am guessing the part that is closer to the firewall but these are only speculations based on my findings. I can be wrong but why two of them "cooked" only on that side? What else can cause that?

[HPIA4v2]

hard to say on the life of o-ring, I have not heard the o-rings leak over time issue, if any very isolated. Overtime a crust of coolant develops around the o-ring sealing it of. I had to use a brio pad to clean the pipes when I did my VP, I resued them and that was 25000 miles ago and no leaks what so ever.

My wild guess, is the leak on gaskets is more commons, for example the coolant manifold gaskets in the back of V8 is spec to be torque rather low so vibration can loosen those 3 screws and leak develop. I use loctite on those screws cause it's a bitch to re-tighten once the intake is back on.

as far as VP, mine was not even leaking at 65kmiles, I misdiagnosed pinch o-ring on WP side, should have pressure test the problem but since alot VP is leaking I thought mine was too.

[fmugur]

I just though of this option since lately I have been using the REST to keep the car warm for a bit after I turn the engine off.
I know some bmw models or other cars have the fan running after the engine is turned off in hot days but I didn't see the reason if the water is not moved through the engine.
I know for a pool heater for example the same thing is recommended and I have done some damage on my heater because I used a timer on the pump although the heater shuts off when no water flow. The pool heater manufacturer recommends to run the pump for a few minutes after the heater is turned off.

The idea is that the burner, in car case the cilinders, build up heat and if nothing is taking the heat away from the fire that just stopped, the temperature goes higher than 108C for a short period of time. How high I don't know but I guess we can measure it. I did see it going up on the pool heater but that system is not pressurized and the temp sensor is right there.

[diyanich]

The law of physics is that heat goes up.Running the pump would speed up the flow,but there would a flow anyway,not as fast,but yet.

Originally Posted by fmugur

I just though of this option since lately I have been using the REST to keep the car warm for a bit after I turn the engine off.
I know some bmw models or other cars have the fan running after the engine is turned off in hot days but I didn't see the reason if the water is not moved through the engine.
I know for a pool heater for example the same thing is recommended and I have done some damage on my heater because I used a timer on the pump although the heater shuts off when no water flow. The pool heater manufacturer recommends to run the pump for a few minutes after the heater is turned off.

The idea is that the burner, in car case the cilinders, build up heat and if nothing is taking the heat away from the fire that just stopped, the temperature goes higher than 108C for a short period of time. How high I don't know but I guess we can measure it. I did see it going up on the pool heater but that system is not pressurized and the temp sensor is right there.

[SlickGT1]

Originally Posted by diyanich

The law of physics is that heat goes up.Running the pump would speed up the flow,but there would a flow anyway,not as fast,but yet.

Wouldn't it circulate through the radiator, and hopefully dissipate at that point? It would also flow heat into the cabin, no? That is what REST does.