924Board.org

Hoboceratops · Joined: 16 Aug 2006 Posts: 156 Location: Atlanta, GA

So I'm pretty sure the head gasket is leaking because I'm getting white smoke at FOT past 4000rpm, my idle is rough and loping, the engine runs a bit hot, and sometimes it stutters on acceleration. However, there is no indication whatsoever of oil in the coolant, or coolant in the oil. The stuttering on acceleration has been around for a while, but the smoke only showed up recently after a long time (hour and a half) sitting in the sun in stop and go traffic; the amount of smoke ejected has lessened greatly since then.

So a few things.

Is this be a leak at the head gasket, or could it be something else?

If it is the gasket and it isn't a large leak, have any of you or people you know had success using metallic block sealant. I've heard only very positive reports about it, and I'd much rather spend 9 dollars on a can of it than rip money straight out of my butt to have the head gasket replaced by a mechanic (I'm super pissed I can't tension the belts myself reliably, I'd do the gasket myself if I could).

The stuttering engine may have been due to the AFM, with rapid changes the voltage would change erraticaly, cleaned and moved the contacts on the strip (Thanks Clarke's Garage!) and upon putting the AFM back in and racing the engine to make a smoke show for my dad dad (it was there but less), the engine did not stutter once. But who knows, maybe the engine was just having a lucky streak, haven't driven it since.

But the big thing is figuring out what the white smoke indicates. I'd love to hear your input on this.

PS - For all the trouble it's given me since I bought it, I ####' love this car so much.

Khal · Posted: Sun Sep 17, 2006 2:36 pm Post subject:

To the best of my knowledge, white smoke indicates burning coolant.

I have an '81 Turbo and although I'm aware the 924S and Turbo engines are technially quite different, to some extent an engine is an engine. In that respect, I'll relate what happened to my car: It seems I had a blown headgasket for quite some time but the engine ran surprisingly well. So well, in fact, that I thought it couldn't be a blown headgasket...
I had no coolant in the oil and no oil in the coolant. The engine ran well, as mentioned, and my only real indication was that it was using coolant and would sometimes be a bit rough at startup. It did blow some white-ish smoke at startup but it was very light and went away once it was warmed up, so I never really worried about it. After finally suspecting dud spark plugs for my rough startup, I pulled the plugs and found that #4 plug was badly corroded. After consulting with a few of the guys here on the 'board and my mates back home, we decided to pull the head (it needed a new timing belt and some other work anyway) and sure enough, the headgasket was blown.

So, although I can't give you advice about the 924S engine in particular, I think I can confirm that an engine can run quite well for some time with a blown headgasket!

Good luck.
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'80 924 Turbo

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

White can only be coolant.

Do the gasket yourself, then have AAA tow it to the shop for the tensioning job.

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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Hoboceratops · Joined: 16 Aug 2006 Posts: 156 Location: Atlanta, GA

Well if I'm going to replace the gasket, it's going to be done during the front engine service, which I had planned doing in a few months once my delicious accident settlement comes in. I really wouldn't like to do it now, as I just don't have the money for it, but after what Khal said, I'm not too terribly worried about it (okay I'm worried about it but dealing), especially since I will be driving lightly until it's replaced. Plus, seeing as how I'm still looking for an emissions guy in GA who will err... ahem... uhh... my lack of a cat and my temp. tag expiration date "fell off in the wash," I'll be going doubly slow.

As of right now though, I'm going to give the block sealant a shot and see how that works out. I mean hell, if people are going 50k after having massive coolant leaks with still no sign of any leak at all just after using the stuff, and even repairing cracks in the block, it's at least worth a shot.

Paul · Posted: Sun Sep 17, 2006 4:36 pm Post subject:

BTDT, wouldn't do it again.

I'd park the car until I could afford to repair it.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Khal · Posted: Sun Sep 17, 2006 4:52 pm Post subject:

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

I don't remember if you ever posted what the model year of your 924S us, but I have written several times that a large number (almost all) 87 924S cars suffer from head gasket failure between 70K and 110K miles.

You should park the car until you can afford to replace the blown headgasket.

Hoboceratops · Joined: 16 Aug 2006 Posts: 156 Location: Atlanta, GA

Yeah, mine is an '87 924S, but it's at 160kmi. Kind of at the far end of the bell curve if they tend to go between 70-110, but whatever, looks like I'm stuck.

Going to keep it parked until I can get the block sealant in, and that should hold well until I go in for the front of engine service and get it replaced. Hell, it'll probably hold for a lot longer, but I'd rather have a new gasket than run with a fixed leak, even if the repaired gasket is functioning properly.

Paul · Posted: Mon Sep 18, 2006 2:28 am Post subject:

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Here's a sad story of how not to take care of your engine, and how not to compound the problem that occurs...

The idiot (teenager) that owns/owned the 87 944 engine that I have on my engine stand for rebuilding right now was/is working at an auto parts store when his water pump started to leak.

I have already spent hours trying to clean the cooling system sealer out of the block passages. I have the seized waterpumo sitting at the side of the car as a reminder (core?) if what happens when you take shortcuts.

Rather than fix the problem properly by replacing the waterpump (scheduled maintenance was overdue), he bought a can of cooling system sealer from where he worked, and added it to his cooling system. The cooling system promptly clogged up, and the water pump seized when it was jammed full of the sealant.

Of course that broke the timing belt, and four valves. The owner's father took over at that point and started helping the young owner. They located an engine, that had supposedly been rebuilt recently, just prior to the car being totaled in a wreck by the Seller who owned and operated the shop where the owner of the totaled car used to have the car service. The Seller of the engine was an eBay Seller (that's where they located him) and a RennList Member if I remember correctly. Turns out that I spoke to this Seller, before the other party bought it as the Seller is located less than 75 miles from here and I was interested in buying the same exact engine, before I have a talk with the Seller, and I decided to pass after I became nervous and unsettled with the Seller attitude and the information he provided me.

The guy that bought the engine paid $1000 for the engine, and $500 for shipping. He spent another $500 on maintenance parts before he installed it. After it was installed, it didn't run right, and the car was taken to a shop where the engine was dismantled when the running problems could not be corrected. The father of the car's owner ended up spending another $3500 on internal engine repairs (actually ended up removing the engine and pretty much rebuiding it, as the work that was done was very poor quality and needed to be redone to get the engine to run properly), and another $1000 to get the engine removed and installed.

All because the young owner did not replace the waterpump (or perform) the "front of engine" service on his car.

It does not pay to do Mickey Mouse Repairs on a 924S. Mechanics do not come in a bottle. Neither do engine overhauls, or cooling system repairs.

Hoboceratops · Joined: 16 Aug 2006 Posts: 156 Location: Atlanta, GA

Paul · Posted: Mon Sep 18, 2006 1:44 pm Post subject:

I learned this lesson in the 70's, when you learn it is up to you.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Hoboceratops · Joined: 16 Aug 2006 Posts: 156 Location: Atlanta, GA

Khal · Posted: Mon Sep 18, 2006 3:08 pm Post subject:

Hoboceratops, is this car your only car/daily driver?

Because if it's not, I can't see why you wouldn't park it up until you can get the headgasket repaired.

Are you able to change the headgasket yourself? You mention being concerned about re-tensioning the belts. If that's your only concern, then I'm sure the blokes here can talk you through it. I believe you need a special tool to do it (gohim will tell you all about that) but considering what you'd save in labour doing it yourself, assuming you're confident you can, I suggest it'd be well worth buying the tool.

I don't know what else needs to be done when putting a new headgasket on the 924S engine but I'm guessing you need to replace various gaskets/seals when you pull the head? Again, the blokes here can let you know.

But the sixty-four thousand dollar question... is your engine due for a "front of engine service"? Is that why you're worried about cost?
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'80 924 Turbo

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW