Re: Bars Leak Head Gasket
***UPDATE FROM THE GUINEA PIG***
I arrived home from the office yesterday and was surprised to see my Thermagasket sealer had arrived in the mail. I ordered it Wednesday night, and wasn't expecting to get it for 7-10 days...anyway. Tough decision - a lot of HUGE college football games on, but since my Buckeyes had already won, I decided to work on the STS instead.
Quick backround...
'98 STS with 116K, recently replaced plugs/wires - noticed wet/orange stained plug in cylinder #7, harsh idle at start-up, increasing amounts of steam in exhaust at initial start up over the last 8 weeks, slow coolant loss of about 1 quart per 750 miles, no overheating.
Procedure...
I followed the instructions provided to a 'tee'. I completely flushed all coolant until only water was in the system. This took some time and patience - probably a couple hours, but is absolutely a necessity, as the coolant will react with the gasket sealing chemicals and clog your cooling passages (not good). Once I was satisfied the coolant was completely extracted from the entire system (including heater core), I partially drained again and added the pre-mixed solution of catalyst and liquid metallic alloy/elemental carbon provided. I then added to radiator through the upper radiator hose. I reconnected all hoses, topped off the system and let the car idle for 20 minutes. It's important that you completely turn the heater off while these chemicals are in the system, unless you don't value a functional heater core down the road. After the idling period, per the instructions, I took the car on a 20 mile highway ride. Returned home, parked it and proceeded with a lot of prayer (not part of instructions).
Initial results...
This morning's conditions: low humidity and crisp temps in the mid 40's. Car started right up with absolutely no indication of hesitation due to presence of coolant in cylinder #7. Not a trace of steam in the exhaust at idle or under acceleration from stop lights. Car ran at normal operating temp and fuel economy was normal.
Future actions...
Per instructions, water/chemical mix should remain in the system for 400 miles before completely reflushing and filling with fresh 50/50 coolant mix. Since my leak was very minor (no cracked head or block), I don't feel the need to keep this product in my system that long. I am going to flush after 200 miles. Also, instructions say there is a possibility of O2 sensor fouling that may be present. Presently I have no codes for this. Plugs may need replacement, but again I don't expect this because my leak was minor and only in one cylinder. Oil change 100 miles after final flush is recommended. For more serious conditions, one might expect the need for replacement O2 sensor, new plugs/wires.
Verdict...
For the short term, I'm elated. The cost of the Thermagasket was $115 with shipping. Not the cheapest alternative - you can get the K&W sealer at auto parts stores for under $8 per can (I think a V8 needs two cans), but as I mentioned in a previous post, the claims of success with the northstar from their website swayed me to this product. I'll repost to this thread in another month or two with an update for everyone. Hopefully the news will be good.
Expense...
Thermagasket + shipping: $115
Two gallons of coolant: $20