VW Polo emission/exhaust problems

FedFrank2

Hey,

I have a 99 VW Polo Classic 1.4 petrol and I got the whole exhaust and catalytic converter replaced just over a month ago. There was something loose in it this week so I took it to have it looked at. That was repaired fine, but the fella who fixed it told me, and showed me, that the cat and front of the exhaust closest to the engine was extremely hot and was turning purple in colour. He said the engine was overheating by a large amount. He said it was something to do with the air and fuel mix and the emissions, and said to have it looked at by a mechanic, as it could worsen into a serious problem.

I had a look under the bonnet when I got back to the house and the coolant levels are fine and I check that and the oil fortnightly. I looked under the car and could clearly see the heat waves coming from the exhaust system.

Just wondering if anyone had ever experienced this before, and if anyone would have an explanation as to what it might be? Would it be a huge job to rectify??

Kevin.

barthek

you sure your temp sensor is showing correct temperature?
is the radiator getting hot when you drive?
have you read the possible error codes with vagcom of some sort?

Mr.Diagnostic

Firstly, do not drive the car. If you have to drive it at all, do so for no more than a few mins.
At best you will destroy the new cat and at worst you will suffer an engine fire.
Did a garage really send you away with the cars exhaust glowing red hot?

If the guy who diagnosed your problem in the first place suggested you go to a mechanic then that would suggest he is not up to speed with this simple system. One would have to wonder why he would be diagnosing faults and fitting expensive parts under these circumstances.

The fault you describe is caused by an engine management/running concern not an overheating issue.

crosstownk

FedFrank2 wrote: »

the cat and front of the exhaust closest to the engine was extremely hot and was turning purple in colour. He said the engine was overheating by a large amount.

A couple of things....

1. It is normal for new exhaust components to turn purple due to heat. Exhaust gasses are very hot and have that effect on metals. Essentially, I don't think it's anything to worry about. The hottest part of an engine is the front end of an exhaust and catalytic convertors can get very hot - 900C is not unheard of. This degree(:rolleyes:) of heat does have some impact on the metal but the metal is designed to take it.

2. You need to determine if the engine is actually overheating. If your coolant temp gauge is behaving normally then you should be OK. If you suspect that the sensor is faulty then replace it - this may give you peace of mind. TBH, if the engine was overheating you would have experienced the repercussions in a relatively short space of time.

If the car is running fine and the coolant level is constant and you've no evidence of coolant in the oil (and vice versa) then I'd be inclined to just drive on.

Mr.Diagnostic

crosstownk wrote: »

It is normal for new exhaust components to turn purple due to heat.

Hi Crosstownk,

My understanding of what the OP meant was that the manifold was glowing red hot rather than just normally hot, hence my warning above. Does a 99 Polo not have a cast manifold?


If it was actually glowing I would stand by what I posted above.
I guess only the OP can answer this one

cheers

FedFrank2

Mr.Diagnostic wrote: »

Hi Crosstownk,

My understanding of what the OP meant was that the manifold was glowing red hot rather than just normally hot, hence my warning above. Does a 99 Polo not have a cast manifold?


If it was actually glowing I would stand by what I posted above.
I guess only the OP can answer this one

cheers

cheers for the responses, the temperature gauge is operating normally, as usual the temperature never goes above halfway. im not sure what a cast manifold is.

i had it done in a fastfit place so im not sure if they know the full ins and outs of the problem. if it helps, it is drinking slightly more fuel than normal. a very reliable mechanic looked at it for me and he couldnt see anything out of the ordinary. although im now having gearbox problems?

crosstownk

Mr.Diagnostic wrote: »

Hi Crosstownk,

My understanding of what the OP meant was that the manifold was glowing red hot rather than just normally hot, hence my warning above. Does a 99 Polo not have a cast manifold?


If it was actually glowing I would stand by what I posted above.
I guess only the OP can answer this one

cheers

I didn't see any reference to a 'glowing' exhaust. But, yes, if it's glowing then it's a lot more serious.

I still reckon it's discolouration due to heat..........

FedFrank2

crosstownk wrote: »

I didn't see any reference to a 'glowing' exhaust. But, yes, if it's glowing then it's a lot more serious.

I still reckon it's discolouration due to heat..........

hi crosstownk,

yes, it certainly wasnt glowing, it was discoloured as you said, when he showed me the chart of what it looked like when it was new, i suppose it put the s**ts up me.