clarification on "goo"

From time to time I get PMs asking why I have such strong opinions about using sealants on gaskets. Most are well presented, but I find that repeating myself has become enough of a burden as to cause me to skip over a point of two and not be as clear as I should.

To that end I am posting a short explanation of my repeated reaction to the many posts that come along that have to do with the issue. I don't think that I am a zealot, just a little older and set in my ways.:)

Hope there is no offence and I certainly hope that the brethren use my points to make up their own minds.

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My obvious aversion to "goo" is born of seeing too many repairs that have the stuff squirting out from between the mating surface's. The blue stuff is apparently attractive to folks who's philosophy is "the more the better", and all of the bright blue mess is very unattractive to my eye.

Another issue that I have is that what ever is squishing out on the outside is matched by the same volume of stuff being squeezed out into an internal cavity, and should some of that material come adrift in there, some very bad consequences can occur.

Beyond those points, the stuff makes life more difficult in both dis-assembly and cleaning. Things can be stuck so badly that damage is done to the parts as they are forced into separation and the clean up process before reassembly can be tripled. Removing a gasket might be a tad tedious but sitting there scraping and cleaning a ton of goo can multiply a repair by several fold.

I encountered a gasket recently that had been "gooed" on and I am still scraping and cleaning in order to get down to the mating surfaces. The time to do a simple repair has exceeded the ordinary by four fold and I am presented with a problem. Should I have scared the heck out of the customer before lifting the first wrench by telling him all of the possibilities or should I just eat the extra time and lose my fanny on the job, or should I just motor on and present the unexpected time billing when all is back in place?:(

I am not saying that I NEVER use sealant. There is a time and place for everything but the wholesale reliance on magic in a tube is wrong.

Jack

I use a variety of sealants on gaskets as I feel apropriate. I don't like leaky engines, and mine don't. Goo squirting out of the edges? That's the fault of the person applying it, not the sealant's.
Furthermore, no-one touches my engines with a wrench but me, so I'm not really concerned about some other mechanic's annoyance with scraping gaskets or inability to separate components without breaking things. ;)

If I were the one charging to do the work I would stand by my quote for the price. Isn't that legally binding anyway? That pretty much makes post operative regrets moot. Quote the price right to begin with. Scaring the customer away with the truth is preferable to misleading the customer with overly optimistic estimates.

My mother bought a brand new 1978 Camaro with an inline 6. When the car was several year old, but very low miles, it developed a noisy hydraulic lifter. I pulled the valve cover and found that the factory had applied so much silicone gasket maker that a blob of it had caught onto a pushrod, then pulled a string of it several feet long and wrapped it around and around the pushrod like a rubber band. So much was built up that it was impeding the movement of the pushrod and must have collapsed the lifter...thus the clacking.

I think it was the late '70s when GM started to fall in love with the silicone "form a gasket" method of cutting costs. They actually thought that they could use it instead of gaskets--what a disaster! That stuff is the worst and probably most misused and misapplied of all the sealants. There are only a couple places where I will use it. Often, I use it on oil pan gaskets to compensate for the usual lack of perfect flatness. I use only the minimal amount applied directly to the gasket and carefully wiped off to a very even thin layer. I apply the gasket to the clean and dry surface of the pan, but on the block I apply a thin film of oil and wipe it back off. I set the pan in place with the bolts finger tight and let it dry. Then I torque the pan bolts to spec to avoid distorting the flange. When I pull a pan that has been prepared in this manner the gasket sticks to the pan and releases cleanly from the block.

Jack

On the olden days they taught mechanics to not use goo. The parts with flat surfaces were made that way on purpose. The gasket was more than enough for machining imperfections. Goo was use to facilitate the gasket replacement to hold it in place for assembly. Gluing the valve cover gasket to the cover, Holding the waterpump gasket to the block for installation. Etc.

When an emergency gasket repair was necessary out came the Goo.

Outboards are famous for Permatex gaskets.

How many times has it taken two hours to change a thermostat because of the goo.

The minimum of the stuff the better.

As an Old Maintenance Engineer I would always increase my labor estimates on a job if I saw gasket sealer.

Larry

I'm with Jack. I don't use goo but don't blame those who do. However, getting the goo out is not part of a "normal" repair and I'd expect a bill for it if it were me. But I wouldn't have taken it to Jack if I didn't trust him, so I wouldn't feel like he was ripping me off. There's all kinds of hidden damages on these cars, it's not fair to expect a mechanic to quote an absolute price and be bound by it if the damage is worse than it appeared.

I didn't intend for this thread to evolve into a discussion about the morality of payment/effort on removing the stuff, but only an observation from my perspective on what I like and don't like about goo.

Some use it others don't. Some use lots and others just a little. To each his own preference.:)

Jack

indian head smells good.

Bill

I have always thought that one should have a license to buy pliers or vice grips. I have seen so many people do bad things with them. These are a senior mechanics tool.

In the early 70s when I was taking community college automotive classes, one of the last sections was automatic transmissions. My lab partner and I rebuilt one in a Dodge Dart, IIRC. The pan leaked. We pulled the pan, double checked everything, then reinstalled it with a new gasket. It still leaked.

Kurt, the class instructor, had said that we were not to ever use gasket sealant on an automatic transmission, since even the tiniest amount that broke free would wreak havoc in the valve body, etc.

Roy, the student teacher (a mechanic retired due to a back injury), said to pull it again and then get him. We did. He walked up, looked around to see if anyone was looking, then pulled a tube of gasket sealant from his coverall pocket and proceeded to apply an extremely thin coating on the gasket. We reinstalled the pan, and no leak.

We knew why there were rules, but this was a great demonstration of why they are sometimes broken.