HOUSTON, WE HAVE A PROBLEM

Well I have been reading this board for a long time, and have used many suggestions. But now I have a problem.

After reading several posts on Oil change, I switched to Castrol 20w-50 this weekend. Today I drove my 911 SC (78) about 15 miles and back home -- no problem. After cranking and driving around the block to put the car in the garage, I smelled a burning, saw smoke, opened the engine compartment, and the heater hose on the passenger side was on fire and the hose from the blower to the air fan was melted. I put out the fire in a few seconds, but burned a hole in the oil line that runs under the air conditioner compressor. When driving home, I don't think my temp was higher than ususal.

My question is do you think the higher weight oil caused too much heat? I did have some tape on the heater hose that may have caught fire instead of just melting. Also, how do I replace the oil line?

thanks in advance,
mlyon

I'm confident your engine did not get hotter. If 20w-50 is thicker than you usual oil it should reduce heat, if anything. Oil leaks could have dripped to the exhaust pieces, which are the only parts that could even get hot enough to start a fire, but that fire would have developed underneath the sheet metal.

Fires generally have electrical causes. Dangling tape is an invitation. Your ignition wires certainly provide enough juice to begin a fire. Are they burned? Inspect them carefully for any absence of, or imperfections in the insulation on those wires.

It sounds like you hade some real excitement. I'd have been pretty stunned by such an experience.

The A/C compressor will probably have to come off to replace the oil line that runs across the top of the chain housing under the compressor, if that's the damaged one. Don't undo the hoses to the compressor. lay a thick towel across the rear quarter panel and hang the compressor there with wire, hoses attached. Just be careful with the bolts at each end of the hose. Start them without cross-threading, and try to be sure the hoses 'seat' themselves at these two end junctions squarely.

Take parts off slowly and try to determine where the fire started. Invite an arson investigator over for barbecue.

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'83 SC

Sorry about the recent fire, but I am 100% certain that it had nothing to do with your recent oil change or the weight of your engine's oil!

The fire, almost certainly, HAD to be initiated by some electrical problem ... air cooled Porsches are just too well sealed in the engine compartment for any exhaust heat to cause paper tubing, with or without loose, flammable tape, to catch on fire!

To your question about replacing the oil line. Just as Super said, the A/C compressor needs to be moved out of the way. Two or three pieces of engine tin will also need to be removed, as will the air hose to the heat exchanger. Hopefully none of the plastic pieces in the air duct/shroud system were damaged by the fire! You need to be very specific about the year of your car and whether or not you have the '84 Carrera pressure-fed chain tensioners installed, when you order the replacement cam tower oil supply hose. You will also need the sealing rings at each 'banjo-bolt' connection, copper for the tensioner connection, and aluminum for the cam tower connection, and a new ferrule for the block connection of the line. A flare-nut wrench is the preferred tool for loosening and installing the ferrule nut connection! Good luck!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 06-07-2000).]

The car is an 78 SC with out carrera tensioners. Also, I caught the fire early and put it out quick. The hose from the heater air deflector to the blower (part #2 page 78 Hayes man) and the hose from the adapter to the passenger heat exchanger was on fire at the point it runs under the air conditioner compressor. The only burned wires go to the oil thermostat (where the fire was located under the compressor). The oil line is located at the same place and was burned during the fire. The engine cranks and runs (I only let it run a couple of seconds before I knew there was a leak in the oil line). None of the spark plug wires were burned. I think the problem is not related to a short, because there are not any other wires in the area except for the thermostat.
Also the shroud suffered no damage, only the parts mentioned.

My plan for now is to replace the oil line and repair the wiring to the temp sensor. Any thing else to check?
thanks
mlyon

[This message has been edited by MLYON (edited 06-07-2000).]

[This message has been edited by MLYON (edited 06-07-2000).]

About 7 months ago on a road trip to Palm Springs I had purchased some engine cleaner at Autozone to clean off my heat exchanger from a pesky oil leak, the Autozone did not carry Gunk but had there own proprietary brand of engine cleaner on sale.

I stopped at a car wash to clean the motor now I have sprayed Gunk many times over the years on hot/warm engines to no effect but some smoke but this Autozone crap was like gas as soon as I sprayed ot on my exchangers it caught fire!
You can imagine my reaction especially since I was parked in a car wash bay but had no spare immediate change to turn on the sprayer and put it out I had visions of running to the change machine and getting change and coming back to a car engulfed in flames so instead I grabbed my favorate expensive leather motorcycle jacket and used it to smother the flames(another good reason to carry a fire exting)
Ended up with a melted jacket but no damage to my car .

I have a 'feeling' that the fire originated at that heater blower motor, or its' wiring ... you should check it VERY thoroughly!!!

You may want to remove it from the engine compartment for cleaning and testing. Another fire, on your workbench, while bothersome, would no doubt be easier to put out and clean up than one in your car.

Yes, it only takes one engine fire to make you very paranoid about having a fire extinguisher at close hand when driving!!! My one and only engine fire while driving came in 1971 ... since then I have bought perhaps 10 to 12 fire extinguishers, including a couple of 5 lb Halon 1211 units!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 06-07-2000).]

And don't forget to post your thoughts. I have removed and disassembled my heater blower motor several times and although I am not finished rebuilding it (perhaps I'm dreamin') I have some understanding of this motor. On mine, one of the two round-head screws holding the case and magnets (fields, whatever) to the brush plate backed out, contacted and stopped the squirrel cage and burned the woven conductor going to one of the brushes. Burned clear through.

These motors can be rebuilt, except I'm having trouble with the front (swivel) bushing. Perhaps the motor dies with this bushing. I have not given up hope though. I have fun fixing stuff.

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'83 SC

FWIW-A lot the new Gunk type degreasers due to smog rules, are reformulated and are used on cold engines.....use on a hot engine will cause fires....