05 Cayenne S Radiator and Misfire anomalies

[Edward White]

Hi folks,

Learning a lot reading through these forums and thanks to all of the contributors.

My Cayenne S 2005 had been behaving itself pretty well up till recently and then decided to play silly buggers. Radiator had been coming on intermittently following cold start and last week it a dropped cylinder followed by an emission light warning as the Cat screamed in protest. In the absence of a compression test, I suspect the misfire is either plugs or coils or both so I've ordered a set of each but am open to any suggestions?

[Loren]

:welcome:

Read the fault codes and report them back here. Without the fault codes everything is just a guess.

[Edward White]

Hi folks,

Learning a lot reading through these forums and thanks to all of the contributors.

My Cayenne S 2005 had been behaving itself pretty well up till recently and then decided to play silly buggers. Radiator had been coming on intermittently following cold start and last week it a dropped cylinder followed by an emission light warning as the Cat screamed in protest. In the absence of a compression test, I suspect the misfire is either plugs or coils or both so I've ordered a set of each but am open to any suggestions?

:welcome:

Read the fault codes and report them back here. Without the fault codes everything is just a guess.

Thanks Loren, those I don't have access to at the moment. Unfortunately I'm 3 hours drive away from the nearest Porsche dealer and don't want to make the journey either for fear destroying the cat so the next best fix is plugs and coils.

[wvicary]

Hi folks,

Radiator had been coming on intermittently following cold start

Do you mean low coolant warning light?

Do not operate the vehicle if the check engine is flashing due to a misfire. Replace all the coils/spark plugs as they are a known fault.

[Edward White]

Hi folks,

Radiator had been coming on intermittently following cold start

Do you mean low coolant warning light?

Do not operate the vehicle if the check engine is flashing due to a misfire. Replace all the coils/spark plugs as they are a known fault.

No it's not showing any errors when the radiator comes on and this is what has me head scratching. It kicks in even when the engine is cold. As for the check engine warning I think I drove about 2 miles to get home when it came on so I'm not sure what damage I could've done over that distance but you guys would probably know better than me. Fingers crossed I haven't shagged the catalytic converter with unburnt fuel going through but will wait and see.

[odix]

A Durametric may be a good purchase for you to pull the codes. Will save you the drive to a dealer.

http://www.durametric.com/default.aspx

[Edward White]

A Durametric may be a good purchase for you to pull the codes. Will save you the drive to a dealer.

http://www.durametric.com/default.aspx

That's darn good of you to send me that link. Many thanks.

[deilenberger]

It's not clear to me what you mean by "Radiator" coming on? Is this a warnng on the dash? If so - have you checked the coolant level?

If it is suddenly low - your cooling pipes may have sprung a leak, and that should be fixed before even starting the engine.

[wvicary]

Or cooling fans engaging at low engine temps??

[Edward White]

It's not clear to me what you mean by "Radiator" coming on? Is this a warnng on the dash? If so - have you checked the coolant level?

If it is suddenly low - your cooling pipes may have sprung a leak, and that should be fixed before even starting the engine.

appreciate you taking the time guys. There's no error indicators on this or fluid loss that I can see it's just the radiator kicking in when it shouldn't and engaging at low engine temperature as wvicary mentioned above. And the damnable thing about it is it stays on and then stops for days at a time. My thinking was a stuck thermostat but maybe you guys might have some ideas.

[wvicary]

There are a few faults that can cause odd/intermittent cooling fan operation, best to report back with the fault codes or it will all be just guess work.

[Edward White]

Just to give a quick update guys and to thank you again for all your help, just popped in a new set of coils and bingo, problem solved but will have to pull them out again next week as the plugs ordered didn't fit. But thank goodness it was just the coils as the thought of having to do a compression test was a nightmare scenario.

But just for interest, each of the old coils that I pulled out showed no external signs of failure and not so much as a hairline crack which I know says nothing but keep that in mind for anyone who encounters the same problem. You may be looking at them through a magnifying glass as I was and see nothing at all.