2000 4.2 Overheats, white smoke from exhaust
07-03-2015, 09:31 PM
#1
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2000 4.2 Overheats, white smoke from exhaust
Hi. I just bought this car... Probably a bad decision...
Long story, please bear with me.
When I looked at it it was dark out. Also the kid cut off the stock mufflers and just left the pipes after the cat. So I didn't think much of the smoke. I figured maybe it was the lack of mufflers.
The car had some extra fan placed on the front of the rad on the opposite side of the accessory fan. The wires to the acc fan were cut and spliced to that. For what reason, who knows.
I noticed none of the 3 electric fans came on. I naively thought that was why it was overheating and this could end up being an easy fix.
So I took out that extra fan, retired the factory acc fan and changed the broken 40A fan fuse. Figured I'd be good to go... No dice.
I let the car idle, with A/C on for a little bit. The electric fans both work. Speed changes on the main fan. Car got up to normal temp and hovered for a little bit. I was happy. Then maybe 5 min later started to overheat.
White smoke from the exhaust happens once the motor starts to warm up, not right when it's started. It doesn't really smell sweet, more just like ****ty exhaust. I smelled a similar smell on a 92 Lexus once upon a time and I swapped the motor because it was super high miles and probably bad head gasket.
I welded the mufflers back on today. Can't believe someone would hack off perfectly good German smooth sounding mufflers. Didn't help the smoke...
Motor starts right up, and no CEL.
Clogged CAT? Head gaskets? Water pump? Thermostat? All of the above?
151k on the odometer. Said timing belt / water pump / thermostat done at 120k.
I've just ordered the service manual. Now considering options for code reading... Could use some advice on that too.
I'm thinking it may be best to just go all out and do all head gaskets and above, clean everything up (misc oil and coolant leaks around engine & oil pan), do belts, pump, stat... It's not registered yet, so I have some time to work on it before my current rust bucket dies.
Any help would be appreciated.
Long story, please bear with me.
When I looked at it it was dark out. Also the kid cut off the stock mufflers and just left the pipes after the cat. So I didn't think much of the smoke. I figured maybe it was the lack of mufflers.
The car had some extra fan placed on the front of the rad on the opposite side of the accessory fan. The wires to the acc fan were cut and spliced to that. For what reason, who knows.
I noticed none of the 3 electric fans came on. I naively thought that was why it was overheating and this could end up being an easy fix.
So I took out that extra fan, retired the factory acc fan and changed the broken 40A fan fuse. Figured I'd be good to go... No dice.
I let the car idle, with A/C on for a little bit. The electric fans both work. Speed changes on the main fan. Car got up to normal temp and hovered for a little bit. I was happy. Then maybe 5 min later started to overheat.
White smoke from the exhaust happens once the motor starts to warm up, not right when it's started. It doesn't really smell sweet, more just like ****ty exhaust. I smelled a similar smell on a 92 Lexus once upon a time and I swapped the motor because it was super high miles and probably bad head gasket.
I welded the mufflers back on today. Can't believe someone would hack off perfectly good German smooth sounding mufflers. Didn't help the smoke...
Motor starts right up, and no CEL.
Clogged CAT? Head gaskets? Water pump? Thermostat? All of the above?
151k on the odometer. Said timing belt / water pump / thermostat done at 120k.
I've just ordered the service manual. Now considering options for code reading... Could use some advice on that too.
I'm thinking it may be best to just go all out and do all head gaskets and above, clean everything up (misc oil and coolant leaks around engine & oil pan), do belts, pump, stat... It's not registered yet, so I have some time to work on it before my current rust bucket dies.
Any help would be appreciated.
07-04-2015, 04:52 AM
#4
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I didnt even have to read your post. You said two magic phrases:
1. "overheat" and
2. "white smoke with sweet smell from exhaust"
Blown head gasket. Causes overheating. Allows coolant into oil and combustion chambers. Results in white smoke and smell.
I bet if you check the oil there will be some white milkiness to it, or maybe a layer of fluid as if rain fell on a bucket of oil.
Grant
1. "overheat" and
2. "white smoke with sweet smell from exhaust"
Blown head gasket. Causes overheating. Allows coolant into oil and combustion chambers. Results in white smoke and smell.
I bet if you check the oil there will be some white milkiness to it, or maybe a layer of fluid as if rain fell on a bucket of oil.
Grant
07-04-2015, 06:23 AM
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Draining the oil will be the second thing I do after a compression test. First flush the coolant and see how nasty that concoction of cheap different colored fluids is.
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07-04-2015, 08:22 AM
#8
AudiWorld Super User
There ARE combustion testers…..
Relatively cheap. But I agree..it sure looks like a head gasket leak. You can also pull all the plugs and look for a suspiciously really clean one. A leaking head gasket will often steam clean the living heck out of the plug involved.
07-04-2015, 08:24 AM
#9
AudiWorld Super User
Think before you put a lot of money into a $5K car. It's not an S6...
You'll probably end up doing a TB service and WP and serp belt at the same time.
Really consider if you want to keep the car. This ain't cheap.
