White smoke from exhaust #!%@

[gniknave]

I'll explain as simply as possible. It has been cold in the mornings here in Northern California lately and usually between 6am-7:30am is the time I'm driving to work. I had been noticing white smoke from my tailpipe when I would first start the car and then for the 1st minute afterwards, then no more.

Then we had our first big rain storm of the season last Tuesday I think. On this day I drove to work and after driving an hour and a half straight (yes my commute is that long) I stopped at a stoplight and saw a little white smoke coming from my exhaust. At that time I wasn't alarmed because I figured it had to do with rain and the cold weather and the fact that maybe a little water got in the exhaust area.

Over the past week since then I have been monitoring m coolant level. It is definitly going down but there are two other reasons for that. 1) I noticed coolant seepage turned to slight dripping coming from the gasket where the radiator cap is.

2) I noticed a small leak from my radiator drain plug area.

It's been 3000 miles since the engine was replaced with an imported one (used). I have stalling, hiccuping, fluctuating idling, low power, delayed shifting...However I also have a small fuel leak behind the plenum which I believe is coming from the fuel damper and may be causing some of the stalling,hiccuping, fluctuating idling, low power. The fuel pump also hums and I'm ready to replace that (I already have a NEW one ready to put in).

Anyway, today it rained hard again and I drove to work with same hour and a half commute. I didn't check for smoke this time until I got home and the car had cooled for an hour. The coolant reserve bottle is where it was yesterday (maybe a little lower- I filled it yesterday and it's a little over the max line). I let the car run for a while to get to normal running temperature and there was the white smoke from the exhaust again! I went back and smelled it, and got a hint of coolant. I then pushed the throttle up to about 4000rpm and watched with my jaw to the ground as white smoke poured out. It just kept going and going and going until I released the idle.

Frustrated and about to take an ax to the car, I pulled it in the garage and shut it off. I know I need to take it to a professional and I don't plan on driving it until then, but can anyone tell me what type of things cause coolant to come from exhaust?

[Jesda]

Failed head gasket. Extremely rare, and usually the result of previous overheating.

[gniknave]

With all of the long drives and city driving (stop and go) that I've been doing, my temp stays consistently just below normal. It has never gone above that. I'm thinking the common sense answer to that is as long as there's coolant then it won't overheat.

Any idea on the average replacement cost of a head gasket on this car? I looked in a labor guide BEFORE this happened and caught a glimpse and I believe it said 23.8 hours for the job. Can this be the only possible cause for the smoke? I never noticed any smoke while driving. Just at idle when warming up. Is it at all normal to smell a LITTLE coolant from the exhaust? I really have to try hard to smell it, it's not THAT obvious.

[DAEDALUS]

A head gasket is the only way I've ever heard of for coolant to get in the exhaust. I mean, you could have a cracked TB I suppose, that was allowing coolant to seep into the intake, but I've never heard of that happening. Also could be a cracked head, but I've never heard of that on a Q. A leaking injector would cause white smoke as well, but it would smell RICH with fuel, not coolant. If the smoke is that dense the smell should be obvious which fluid is causing it. An overheat is not uncommon with blown HGs. The pressure entering the coolant system from the cylinder can alter the flow of the coolant, create gas pockets and force coolant out of the system.

[carlos_knology]

It definitely sounds like a head gasket. My trusty Toyota Supra did the same thing (a common Supra failure, btw). White smoke, a hint of coolant smell from the exhaust.

Your post mentions that you have a used engine. Perhaps the overheating took place while the engine was in the previous car.

Anyway, the good news is that it's a cheap part, the bad news is that it's lots of labor.

[gniknave]

Funny you mention it could be a leaking injector. On Sunday I noticed a very rich smell coming from my exhaust and my check engine light has been on intermittently (sometimes for a whole trip, sometimes on and off in a few secs). I know my passenger side O2 sensor is probably fried because I need a valve cover reseal on that side and oil is leaking straight on to the sensor. I had a feeling that this is why the exaust was rich. One thing though is that I didn't notice any smoke at all on Sunday while the car was warming up (sunny day, 70 degrees outside).

I work in a shop that services Honda's and Acura's [BARF] and I probably smell rich exhaust and see white smoke from tailpipes at least 2-3 times a day. If you smell rich fuel, and coolant smells too much it becomes hard to tell the difference at times (some probably wouldn't agree). I'm thinking that last night I tried so hard to determine the smell of the smoke from my exhaust that it almost seemed like coolant. However the amount of coolant I'm losing from the reserve bottle seems related to the leak from the radiator and dripping from the radiator cap/gasket area, but not from burning from exhaust. The amount I'm losing just isn't that great. The check engine light and crappy gas mileage I'm getting + the fact that the injectors I'm using are the same ones that came with the used engine makes me believe that it actually is a leaky injector, not coolant. Especially if this is a rare condition. Actually this is what I'm praying for! The engine only has 85,000 miles on it btw.

What is the average or recommended mileage to replace injectors? Has anyone heard of, or had a case of a blown head gasket from a 90-93 Q? Is it worth having this work done if it is a head gasket?

[Q45tech]

Use a combustion gas tester to check for hydrocarbon gases bubbling into coolant. It is always a two way street especially at idle.Head gasket leaks on Q are very rare.

When you use JDM [or domestics] for engine swaps the highest cost is the engine external R&R before you put the replacement engine in.

[gniknave]

Thanks Q45tech. Last question. What is the average or recommended mileage to replace injectors?

[911/Q45]

Replace them when they go bad. I lost one at less than 20K, another at 60K and a third at 75K, when I decided to replace the rest preventively as well as the one replaced at 20K(8 years earlier).

[gniknave]

Ok now it's intense white smoke from exhaust after not driving the car for 2 days. I also noticed my coolant level went from above maximum, to just below maximum in 2 days of not even driving the car. I smell coolant in the engine area whe the car is running. I checked the valley and it's as dry as a desert. Smoke smells more like fuel than coolant but could be a mix of both.

I do remember that when I re-filled my reserve bottle with coolant that I didn't mix it well with water (the coolant wasn't premixed). I didn't put much water at all actually. Would this cause it to burn? Is the reserve bottle SUPPOSED to go low eventually? What happens if you don't mix the coolant with water at all?

[DAEDALUS]

Don't run the car except to diagnose. If it's fuel you can ruin your 4-figure cats. Worse, you could have an explosion or hydrolock. Do as Q45tech said and peform a combustion gas detection after fixing all known coolant leaks.