My ''91 G20 started emitting white smoke while idling today. I guess my head gasket is on the way out, after ~220K miles.

I'm going to have to get a mechanic to do the work, as this isn't something I can tackle solo.

What should the job cost? I have no idea. Ballpark estimates from those who have been there would be appreciated!

In all honesty, its probably cheaper to put a used JDM engine in.

True, if you don't do it yourself it will probably cost as much as 2 JDM SR20DE. If you do it yourself it cost no more than $60.00 including oil, anti-freeze, filter, head gasket.

I did some reading on the used engines... ~$600 shipped + labor for an engine with under 50K miles sounds damned attractive. This depends on the labor charges, though...

OTOH how difficult is it for the do-it-yourselfer? Would I need a hoist in order to do the job?

it is an idea, but the labor for putting the motor in and the price of the motor will be much more than doing the head gasket, if you like the car a lot and plan on keeping it for a while, then definately put the jdm in otherwise I would just do the headgasket as I would imagine it would be cheaper with all included for both...., of and if you can't do the headgasket I wouldn't attempt the motor swap by yourself...
Sean

Wups! Didn't make myself clear. How difficult is the head gasket job for a DIY mechanic with some instructions and a steely look in his eye? :)

Get someone to help you do it. Its fairly simple. I have done a few Headgaskets with help from one other person. Just get a fsm.
It took about total of 8hrs to do it. Although if you have the money to spend on a new motor and dont care , i say go for it.
But as long as the deck and head are not warped i wouldnt put a new motor in. If you need more info let me know.

I talked with my mechanic today regarding the SMOKE. Based on my description he thinks that my valve seals are old, hard and not wiping as well as they used to.

Here's a more detailed description, tell me what you think.

- I often leave the car idling with the A/C running. Its summertime here and can get bloody hot during the daytime. Yesterday was a real scorcher... 90+ degrees and no breeze! Anyway. After returning to the car after it had been sitting and running for about 15 minutes there was a bit of white smoke coming from the exhaust. It went away as soon as I started driving, but returned at the next 'extended idling stop' (drive-up fast food, ~10 minutes?) No smoke later on that day and no smoke when I fired up this morning.

I don't seem to be losing coolant. I did add a bit to the recovery bottle this morning, but the radiator was full. I also didn't see any oily residue or deposits in either the radiator of the bottle.

Oil seems normal. (I use Mobil 1 10W-30) The level is high though.

It's about time for another oil change. I think I'll have them flush out the cooling system as well, just to be sure.

I would think if you had a blown headgasket you would see:

1) Frothy oil
2) Loss of Power
3) Loss of coolant
4) Sweet smelling exhaust


Now, you confirmed you don't have number 1. However, I haven't heard anything about number 2 and 4. You said you lost some coolant out of the overflow. Well, that's where the engine would pull coolant from if it needed some. Therefore, I would say you ARE using coolant. Don't get me wrong, some use is normal. Emptying the overflow bottle in one day is NOT normal. I'd day a 1/4 of it in a few months time would be normal, expecially if it's how as you say it is.

In terms of it smoking only at certain times: when you idle, the thermostat opens and circulates coolant into the engine block. That's a particular point in time when it COULD leak at the headgasket and cause the white smoke. I would deduce the rest of the time that the thermostat stays semi-closed because the moving air from the car moving and the fans would keep it cool enough not to need the coolant flowing through certain areas of the engine. Therefore, there wouldn't be a lot traveling around in the block/head.

These are all guesses and based around some experience I had with a friend and his CRX. I would suggest a leak down test and a test of your compression. If the compression is low on two cylinders right next to each other, then you have your answer, hopefully.

Have it tested and report back.
Curt B. Shumaker

Good info. Your point about the thermostat opening at idle and circulating more coolant to certain points in the engine makes a lot of sense.

More detail in re: your points.
1. the oil isn't frothy or burnt. The level is high because I overfilled it. :stupid:
2. I've not seen a dramatic change in power lately.
3. the coolant loss is a tough one. Its been months since its been looked at - probably around the time of the previous oil change. The overflow reservoir wasn't dry, it was just under the 'min' mark. I refilled it to the 'max' point. I'll have to monitor it over a couple of days to see what happens.
4. I wouldn't refer to the smoke as sweet-smelling. It was nasty stuff. I honestly feel that it was coolant, not oil - the smoke was white, not blue, and didn't linger like oil smoke does.

I also swirled a finger around the inside of the (cold :)) exhaust pipe this AM... nothing but dry black soot. No oily residue.

I don't think you have a blown headgasket. I think it might be leaking every so slightly, but I don't think it's blown. If you were blowing out antifreeze from your tailpipe, it would smell sweat. If it was blown the oil would be frothy and you would have no power.


I think that it's leaking. I still say have a leak down test and the compression checked to confirm. I would also fill that overflow bottle up and watch it for a few weeks. If you blow through an entire tank in two weeks, then you do have a problem and it might be the water pump and not the headgasket.

I still say a loss of power is a big indicator if it's actually blown vs. leaking.


Good luck
Curt B. Shumaker

If you want to use good parts and do it yourself it will cost you more than $60 as quoted earlier. An OEM head gasket is $45 and you would probably want to get your head checked out. My resurface job was $75. Then depending on what oil and antifreeze you put in that might cost you another $30 with the filter. If your not a mechanic this is a bitch to do let me tell you because I had to go through this last week. Good luck.