Stargazer writes:
I have a slight head gasket leak in a 1993 GMC van, 350 cu. in. engine. I know that I will have to replace the gasket eventually; however, a friend suggested a head gasket sealant. This sealant drops into the radiator, and seals the leak. This friend had worked on cars professionally, so his recommendation has weight with me. Would you recommend this fix for a one hundred mile trip? I need the van to tow something.
Sajeev responds:
TTAC certainly has a lot of readers with vans. Which is somewhat awesome when you stop and think about it.
I think these gasket sealers (or block sealers) are a mixed bag. They can work, depending on the gasket’s condition. On a small block Chevy with iron block and heads, the odds of a quick re-seal are in your favor. Hell, it might handle the rigors of towing “without a hitch.” (Thank you, I’m here all week. Tell your friends.)
If this van is a keeper, there’s a downside: the cooling system gets coated with leftover sealant, making for a colossal mess for whomever tears into this motor. Who knows, you might need a new water pump or heater core after all is said and done.
If it’s not a keeper, then you have two distinct moral paths. There’s the path of righteousness and a path more, um, frequently chosen. Using such automotive band-aids so your hooptie van lives long enough to find a new owner is less than honorable. If greed is good, this is how you make some cash. But if you’re like me, you’ll tell the van’s next owner what you did, why you did it, what they could experience in the future. And maybe, just maybe, this is why nice guys always finish last; or why every van eventually winds up in a junkyard.
Technical question? Email Piston Slap: sajeev.mehta@thetruthaboutcars.com
Is replacing the head gasket that difficult?
Seems like something you could do over a week- little bit each day.
Like Sajeev, I’d advise against a sealer if you plan to keep the van. And really, for a trip on which you’re going to tow something, I’m not sure I’d trust it entirely. I’ve used the stuff before, mostly during my used car days to limp something through the auction (yeah, I know, but you do what you have to do), but my opinion of it is that it’s really just for that purpose; a stop gap to get you by. The best —and in my mind only— solution if you’re hanging on to the van, is fix it right. It’s worth the while, and you won’t risk damaging other components or clogging your radiator.
Also remember that you can buy a different form of sealer. If you go to a shop, they can loosen the head bolts, making a tiny bit of clearence between the head and the block. then they’ll insert a type of expanding caulk/gasket maker to fix the problem. after retightening the bolts, it’ll spread this goop out effectively resealing the coolant. this is an intermediary (in every way: time, price, quality) between the two choices you presented: replacing the gasket (not worth it IMO) and sealing it through the coolant (never done it before so idk…)
Another problem with the sealant is that while it is probably OK for just motoring around, it may not work under stress, such as towing, where the engine works hard and throws off a lot of heat. (This was the big problem with the small block 400, it was designed for high torque and towing applications but it was a siamese-bore block and ran hot under stress and the gaskets blew between the cylinders – but I digress).
Gasket replacement on a small block is generally easy, but this being a van, I don’t know. I believe you can access a lot of the engine through the hatch in the passenger compartment. Also, being a ’93 it may be a SB-II block which is different in cooling flow from the traditional small block (’91 and earlier); you need to make sure that you have the correct gasket and not a standard small block gasket.
If it doesn’t leak a lot and you are only going 100 miles, just bring a bucket of water along for the ride and add as needed (once the motor has cooled a bit of course).
I’ve had no good experiences with these sealers and in fact had some bad ones. Some of them fill the cooling system with gunk.
There is no way I would try fix-in-a-can in hopes of getting through a 100 mile trip. There is also a distinct possibility of the head gasket leak allowing coolant to get into the motor oil, which is a whole lot of not good.
To paraphrase one of my favorite rides in Disneyworld…
Absolutely not!
Wouldn’t tow anything for a hundred miles with a blown head gasket and even a tanker full of water along for grins.
Neither would I risk a quick fix sealer and tow something a hundred miles. Not happening.
Huge gamble. What would it cost to tow the van and whatever you’re towing to some on-the-road emergency repair place? Or some local holding facility? THEN repair it to get it back home – or tow to a salvage yard after all that?
I’m just not that sadistic.
If the motor’s been getting extra hot and cooling down for a while something else might have warped. I know that changing the gaskets in the van is a total pain, but it’s worth it but make sure it isn’t burning oil or making noises from the guts. If someone else does it for you just make sure he/she doesn’t charge you more than the vehicle’s worth…there’re a lot of cheap vans out there right now…
…or you can just get that ferrari dino…HA!
As the others have said, don’t use it if you plan on keeping it. This stuff really does awful things to the cooling system. I have even seen them make head gasket leaks worse, by clogging coolant passages and increasing the pressure on the head gasket. Clogged heater cores also. That is a worse job than the head gasket.
Mechanic in a can is akin to no mechanic at all. If your van is in good condition otherwise, and if you are attached to it in any way, fix it properly. I don’t have experience with van clearance issues, but the 350 is an easy motor to work on, and very durable. I am kind of surprised that you have a head gasket leak.
Put an ad on your local Craigslist page for the van, set the price at around $500 or less, and mention the head gasket issue in the ad. It will probably move pretty quickly. You’ll probably find someone out there that has a good motor they want to put in a van or someone who likes to buy vehicles like this and wrench them back to life on their own. Put the cash towards another beater van or truck, or rent a pickup from U-Haul for the tow job.
Uncle Nate used to move some used cars for giggles. He took me around when he was getting one fixed up for me. They always poured in a can of bars leak.
I’ve never had occasion to use it myself, but had a couple of different guys, back in the day, tell me that if you do you’ll never get heat out of the heater again.
No one mention the old “pepper” or “raw egg” trick yet?
Sheeesh, kids today.
Relying upon those onboard electronic brain things way too much.
How much does it really cost to get the head gasket fixed? And if you get it fixed, how long would you expect the van to last? I mean if it costs, say, 8 C notes and you get a year out of it without much other trouble, you win!
In ’85, I bought a 77 Toyota Corolla for $450. Every year I had to put several hundred dollars in repairs more into the car than it was worth. And every year the car gave me cheap, reliable transportation. If I had followed that don’t-put-more-into-the-car-than-it’s-worth rule I wouild have ended up paying a lot more for transportation.
Love Piston-Slap!
My brother tried the same fix on his ’85 Toyota pickup. It clogged up the radiator and the gasket still leaked. It was $190 for a new radiator plus he still had to fix the gasket. Fixing it right will give you peace of mind on your 100 mile towing trip.
Rent a van for the day $$$ vs Time to replace headgasket vs Quick Fix and possibly your van is inworse shape/unsellable.
There´s something spiritually uplifting about a good job. Conversely, there is something inherently bad in a messy quick fix.
My 2 (Euro) cents: If you can do the job yourself, just change that gasket, and take detailed pictures of the process.
* If you keep the van, you will have a better van and the personal satisfaction of being you the one who takes care of it.
* If you sell, the pictures of the maintenance processes are going to be worth something.
I’ve never seen these miracle cures work. On top op of that there could be other reasons it is leaking like a crack somewhere or warped head from overheating. Vans are harder to work on but a V-8 is easier than a front drive V-6.
Pop both heads and replace both gaskets. Won’t cost all that much and you’ll have more confidence in the vehicle. Save the receipts and show a prospective buyer you fixed it right, that will build confidence in the purchase.
Sealants are good for two things:
a) Transfering cash from your pocket to the seller’s/manufacturer’s
b) Clogging your heater core
If it is just leaking coolant to the outside, I wouln’t be overly concerned. Just carry a gallon of pre-mixed coolant until you get around to replacing the gasket. If it’s leaking into the oil (white blobs on the dipstick) or into the combustion chamber (white smoke/steam in the exhaust) then immediate gasket replacement is advised.
Like others have said, if you’re planning on keeping it, don’t use the stuff. If you want to unload the van, clean around radiator cap and rinse out the overflow tank with brake cleaner to hide evidence of oil or the sealer.
There’s only one brand of sealer that works consistently that I recommend: AlumAseal. Comes in a little tube, the stuff inside looks like silverish sand. Full disclosure: I don’t own stock in whatever company makes AlumAseal, unless Altria Group owns the company.
Replacing a head gasket in and of itself is not that difficult; getting at it in a full sized van I don’t know about.
Enterprise rents cargo vans for reasonable rates, except during moving season they’re more and usually booked. This may be an alternative worth looking into.
I agree with the others. Rent a vehicle (which is incredibly cheap in my area – south Florida, for some reason). It would suck to be stranded.
Fix your van the right way or not at all. Anything you pour in to stop a leak is going to be bad for everything else – think about it.
The head gasket replacement job wouldn’t be so bad to do yourself, except for the access part in a van.
If you don’t fix it and you want to sell it, don’t lie to the buyer. What goes around…
Ditto with my 93 180,000 mile V-8 F-150. Oil was fine but coolant was dispapearing. I only drive the truck around 5,000 a year anymore. Sealant fixed it just fine (switching from a 13 psi to 7 psi cap was also part of the fix) and if I get another 15,000 miles (3 years)out of it I will be thrilled. If the sealant had not worked it would have been a trip to the junk yard, collect my $200 and move on. Can’t see spending all the time and money when tomorrow the trans may fall out. Last car I changed a head gasket on had no air, np PS, a two barrel carb with tiny single stud air cleaner, etc. That was maybe a 4 -5 hour job. With the mess under the hood today I can’t even estimate how long a shade tree-er like me would need. Break off even one exhaust stud (almost a given on an engine this old) and it really does become the job from hell.
There’s no way in this world that a glop of “sealer” floating around your cooling system can stand up to cylinder pressure under load. Once combustion gasses blow past the head gasket, the water jacket is pressurized, and coolant flow stops, or is drastically reduced … hence, overheating.
I agree that this snake-oil stuff might work for a little while under very light load conditions, but as soon as you start to apply some serious load, cylinder pressure goes up, coolant flow stops, and it’s game over. Now, in addition to a failed gasket, you have a cracked head as well. Do not drive it.
Didn’t even know such a sealant existed.
Blah… just change the stupid head gasket. It’s a small block chevy, you should find that even at a drugstore… and dirt cheap.
Great comments. Since the van is a keeper, it looks like I’ll have to roll up my sleeves and replace the gaskets. Thanks for the help. I’ll let you know how it goes.
Bravo. And score one for the good guys!
two words
Liquid glass
The name sez it all
Obama puleeze