Engine and Cooling Sealers - PeachParts Mercedes-Benz Forum

dquance · #1 07-20-2010, 11:05 PM

Folks: I have been attempting to research the above products for use on
my 87 300TDT with the original head.
My problem:
About 5 years ago I noticed some oil droplets in the coolant reservoir.
Coincidentally I also had a weeping side tank on the radiator.
After replacing the rad the oil droplets stopped.
I have more recently noticed the upper rad hose is hard when the engine
is cold, a sign of pressure buildup in the coolant.
Possibly a head gasket or cracked cylinder head.

Car runs fine, no overheating or other issue.

I understand the proper fix would be to remove the head etc.
I am concerned it could be a cracked head, which may be more trouble than
the car is worth.
I am not sure I want to get that involved if one of these head gasket
repair products will do the trick.
I only put about 6-7 Kmiles/year on the car.

Has any one used these products specifically on a diesel?
Results please.

A couple that seem promising are:

Blue Devil Engine and Cooling Sealant $60
K&W Permanent Head Gasket& Block Repair w/Nanotechnology $15

Thanks for any input.

Doug Q

scottmcphee · #2 07-20-2010, 11:30 PM

Some people use these sealants to try and sell a car.. they might help for 3 months. If it seals cracks in heads and gaskets, what else is it plugging up? Repeated use may start restricting flow through the rad, etc. If it's an emergency and you need to get the vehicle home a few hundred miles away and don't want to pay the tow... sure. When goo starts going into fluid fill holes just to keep it driving, the car is done.

vstech · #3 07-20-2010, 11:34 PM

where are you located?
these are one year only cars, so "more trouble than it's worth" is a relative term.
I love mine, and I will do whatever is necessary to keep it running. scour the wrecking yards and find a 350SDL or a late 90's SD and pull the head then change it to yours! you'll get the latest #22 head, and your car will be the better for it.
I'd not put any gunk in the motor, especially if I had just put a new radiator in the car!

H-townbenzoboy · #4 07-21-2010, 02:31 AM

I'm with the others. Fix it once & fix it right!

ah-kay · #5 12-20-2010, 01:53 PM

My 300SDL is losing cooling slowly. The coolant warning light comes on about once every 2 weeks, may be longer. I add about 1/2 quart and it is happily on its way. The car runs well, no oil in coolant, does not burn oil, does not overheat EXCEPT the coolant hose remains hard even when the engine cools down.

I suspect it is a very very minute leak on the gasket. It could be a hairline crack on the head ( #14 ) but I suspect it is the former as I have done 45K on it like this. It has not become progressively worse. Car has 289K now.

What can I do to fix it? Really do not want to pull the head to inspect it. It is more trouble than it is worth as it drives well. My options, in order of preference, are:

1) Leave it the way it is and keep topping up coolant when the warning light comes in. And get a lower pressure rating expansion tank cap and let the pressure vent out.
2) Use head gasket sealant, like Blue Devil. My plan is to by pass the heater core first. Any one has experience with Blue Devil? It seems to have good write-up.
3) Change the head gasket but I know I am not up to it and it could open up a big can of worm. I have the resources to farm it out but I do not think it is worth it nor it is at the must-do stage.

What other options I have? Your inputs are appreciated.

jonbobshinigin · #6 12-20-2010, 02:09 PM

I tried some Bars stop leak for a bad head gasket on my 190E...worked for a month or so and then had a lot of issues. Now I am pulling the head wishing that I had not bothered with it. Not for any other reason other than a fear that I put stuff in the coolant system that probably is not going to help anything in the future.

My 1987 300TD Wagon is doing the same thing by losing coolant. I am beginning to wonder if it is my lower radiator hose or something because I am not blowing coolant from exhaust and no oil in coolant or coolant in oil as far as I can tell. I am adding a half gallon of water once every 2-3 weeks now. Distilled water.

Anyhow, my plan is to do it right and I am looking for a newer head while I have the time and it isn't urgent. If I am gonna pull the head, I am not putting a #14 back on it!

winmutt · #7 12-20-2010, 02:29 PM

Quote:

Originally Posted by jonbobshinigin

I tried some Bars stop leak for a bad head gasket on my 190E...worked for a month or so and then had a lot of issues. Now I am pulling the head wishing that I had not bothered with it. Not for any other reason other than a fear that I put stuff in the coolant system that probably is not going to help anything in the future.

My 1987 300TD Wagon is doing the same thing by losing coolant. I am beginning to wonder if it is my lower radiator hose or something because I am not blowing coolant from exhaust and no oil in coolant or coolant in oil as far as I can tell. I am adding a half gallon of water once every 2-3 weeks now. Distilled water.

Anyhow, my plan is to do it right and I am looking for a newer head while I have the time and it isn't urgent. If I am gonna pull the head, I am not putting a #14 back on it!

There are alot of places for coolant to leak out. 1-2 gal is excessive.

jonbobshinigin · #8 12-20-2010, 02:36 PM

Any suggestions as to where I might find such a leak? I suppose the OP and a couple of us should do a coolant pressure test, Ive not done one before though.

winmutt · #9 12-20-2010, 02:42 PM

Look around all the coolant joints. In my case the PO had used the wrong bolt on the water pump/fan clutch after replacing the radiator and the fan put a pinhole in the new rad. A new water pump, fan clutch, and radiator later I am now leaking at other place but my consumption is reduced greatly. Sweet smelling hvac?

jonbobshinigin · #10 12-20-2010, 03:12 PM

No, it does not appear to be from my HVAC, although it had been quirky stuff which is from the control unit I think.

ah-kay · #11 12-21-2010, 01:13 PM

Any members with experience with Blue Devil? I want some users experience before I pull the trigger. I bought it already.

Please refrain from suggesting to do it 'right' and change the head/gasket. It has been like this for 45K miles and I can take the car across country with a gallon of coolant in the trunk so taking the head off is just not worth the hassle or risk.

JHZR2 · #12 12-21-2010, 04:34 PM

It is the fact that you will eventually degrade the waterpump or radiator that concerns me. I think your oil drops were ATF, the pressure is another story, and I doubt it will work given that the pressure is going from the cylinders to the water - it will just blow out.

GM does use some cooling system pellets for sealing purposes. If I was to use anything, I'd use those.

ah-kay · #13 12-21-2010, 06:16 PM

Quote:

Originally Posted by JHZR2

It is the fact that you will eventually degrade the waterpump or radiator that concerns me. I think your oil drops were ATF, the pressure is another story, and I doubt it will work given that the pressure is going from the cylinders to the water - it will just blow out.

GM does use some cooling system pellets for sealing purposes. If I was to use anything, I'd use those.

I don't have oil in radiator or problem in radiator ( new ).

Any head sealant works on the principal of 'water glass' or sodium silicate. The liquid sealant will turn into glass when it is subjected to high temperature ( gas from the cylinder ). Therefore, in theory, should seal any gasket failure if enough glass is formed. The problem is that the existing gasket failure may be fixed but other weakness in the gasket may open up, if there is any. My leak is very minute and the Blue Devil sealant should work. I bought it but I have not decided to use it. I changed out the radiator cap to a lower pressure one and if it works then I will not use the sealant.

It 'should' not clog up radiator, heater core or engine block as the temperature is not high enough to turn it into glass. But who knows. That is why I seek your infinite wisdom.

JHZR2 · #14 12-22-2010, 09:47 AM

Still, is the coefficient of thermal expansion of the iron, the headgasket and this stuff the same? If no, it is still a finite number of thermal cycles before it is no longer there. Then what happens to that "chunk" of glassy substance in there? It is then grit which goes through the water pump and lodges itself someplace in the system.

These are quick fixes for specific issues, not long-term repairs. IMO a low pressure radiator cap is going the wrong way, the high pressure gas is going into the radiator system. Lower pressure cap means there will be less resistance and youll be venting through the cap more.... Likely causing more entrainment of nasties in the coolant and also speeding evaporation of same.

GregMN · #15 12-25-2010, 09:57 AM

Blue Devil does not work for gases leaking into the cooling system, only for coolant leaking out of the cooling system. That is from the Blue Devil customer service person.

Check the overflow tank in the fender well for missing coolant when you cannot find a leak anywhere. Follow the hose out of the filler neck on the expansion tank and you will find the overflow tank behind the inner fender liner. If it is full, you have a defective cap or a compression leak into the cooling system.

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