Can an EGR valve not working properly cause this problem?
 

A problem with some person from Dallas Texas says he can be driving along for several miles and all of a sudden his water temp goes way up, the air conditioner stops working. The temperature comes back down and the air conditioner starts working again. This would seesaw back and forth a few times, but at other times it doesn't happen at all. Not a coolant leak and fans are working properly.

My car has been running real bad with the check engine light coming on after sometimes a mile, and at other times maybe 25 miles before the check engine light would come on. It seems to come on quicker when I am not pushing the car a little too hard. Translation... (When my wife is riding with me. :lol:)

Yesterday on a 90 degree day up and down hills about 65-70+ mph my car started the temp rise a ways and then after a few minutes, not many, the temperature would drop back down to normal… each time this happened, the air conditioner fan kept blowing air, but the cooling stopped. Higher rpm in a lower gear would bring temp down and the air conditioning cooling automatically would just happen. Did it about 3-4 times the same way.

The EGR valve re-circulates exhaust gases into the throttle body to decrease combustion temperature and thereby reduce NOx and improve fuel consumption

My question is... Can a defective EGR valve cause combustion temperature to increase enough while not preventing the NOx, which could also cause excessive temperature, result in rough running and at times a rise in coolant temperature?

Getting up to normal temperature is pretty much a prerequisite for the rough running and check engine light to occur... on our SVX.

We need a break on this rough running, ck engine light, and up-down coolant temperature problem.

All input appreciated…

Keith... always:confused:

Re: Can an EGR valve not working properly cause this problem?
 

Sounds to me like you have a stuck thermostat. One that opens just enough when the car gets really hot and then the whole process repeats.

Re: Can an EGR valve not working properly cause this problem?
 

Not even close:(

Re: Can an EGR valve not working properly cause this problem?
 

You said the CEL is on. Did you pull the codes or no?

From what I can tell about the EGR system, it plays a relatively small part in the overall scheme of the engine. Definitely not enough to make the engine run rough AND make for a rise in engine temperature. This is why I figured you might have a somewhat stuck thermostat.

Re: Can an EGR valve not working properly cause this problem?
 

Could the water pump cause it? Like if the pulley was seizing up or something?

Re: Can an EGR valve not working properly cause this problem?
 

Kwren... in short, no. My SVX runs no EGR at all and never exceeds temp. The EGR is not to cool the engine but it is more or less an emissions standard. The only thing that the EGR can do to make the engine run poorly is stick open, when this happens it fouls the charge at low RPM and at idle.

Tom

Re: Can an EGR valve not working properly cause this problem?
 

Thanks everyone. Back to the drawing board:(

I suppose this sentence about the EGR valve from SVX Subaru "book"...
(The EGR valve re-circulates exhaust gases into the throttle body to decrease combustion temperature and thereby reduce NOx and improve fuel consumption)
...would be too minuscule to make that big of a difference. Especially if it just has an emission function. I was just trying to piece it all together. you know, not cooling combustion gases when added to the NOx that is happening would both raise temperature and my temperature rise was at a time when the engine was at a maximum load.

The water pump seized would be easy to diagnose... Just follow the smoke signals from the burning timing belt which would occur in seconds.:lol:

My thermostat is new.

The rough running engine is the cause of the rise in temperature which is a rare occurrence ... not the rough engine, but the rise in temperature above normal... that is very rare.

After the car gets to operating temperature the rough running and ck engine lite are a way of life.

I don't know, but I think the computer may add some stuff to the equation, or sense something that is detected when the coolant gets to operating temperature.

Thank you Manarius for the input. I was in a mad rush to get on the road when I quickly saw your reply and didn't want other people to read it and think "problem solved" :lol:.
Your question about checking the codes can be answered in the affirmative... if checking it just about every 15 minutes for the last 4 months counts. :lol:
again, sorry I was so short.:(

Thanks again... TomsSVX... wannarace928... Manarius...

Any more things come to mind, just whistle!

Keith:)

Re: Can an EGR valve not working properly cause this problem?
 

my point was the increase in combustion temperature should not be past the threshold of a good radiator. you should not be overheating due to the lack of a bad EGR

Tom

Re: Can an EGR valve not working properly cause this problem?
 

What about rough running and check engine light?? 02 code all the time I replaced them both... 2 times:(

I can make it stop running rough usually and make the ck engine light go out by petal to the metal and 5500-6000 rpm and it smooths out a while. Like I said, aggressive driving can get me about 25 miles of pretty smooth traveling but driving like the rest of you people... like old people... the ck engine light comes on as soon as I reach normal operating temperature.

I really need to get this worked out:(

Keith

Re: Can an EGR valve not working properly cause this problem?
 

Subaru radiator about a year old. Fins cleaned on the ac condenced and radiator as well
Fans work as should.
???? :confused:

Re: Can an EGR valve not working properly cause this problem?
 

Thanks Tom.
I understood the point... Guess I was just wishing:(

Thanks for all of your help... always

Keith

Re: Can an EGR valve not working properly cause this problem?
 

Giday Keith, the EGR can cause the rough running but I can't see it causing the rise in temp.
The EGR starts working when the engine is up to temp and the throttle is at cruise position. If you push the throttle down the EGR closes. This seems to work in with the way the trouble comes on for you.

There is another component in the system the BPT valve, this looks at the exhaust pressure and varies the amount of exhaust gas that the EGR valve passes. If this valve is inoperative the amount of gas fed into the inlet will always be at maximum, to affect the running at cruise. This can also cause the O2 sensor to read an abnormal signal that it can't relate to any other component, so it gives a code.

I can't see this causing the way the temp changes. The engine can't produce a higher temp when the amount of burnable gas in reduced by the EGR, the temp has to be reduced in the combustion chamber, hence in the water also.

Harvey.

Re: Can an EGR valve not working properly cause this problem?
 

Thanks, Harvey!
Something to chew on. (Texas talk) :lol:

Will try to find out about the BPT valve. Have some information that will help me find it! :cool:

Take care,
Keith:)