I have a 95 Blazer with 160,000 miles. It just sprung a significant coolant leak which is dripping from the rear of the engine behind the oil pan. My mechanic tells me it's either a cracked block or a rusted out freeze plug. it has not been cold here in Michigan, so I suspect it's a freeze plug.

The problem is you can't get to it without removing the front wheel drive transmission which is big bucks. No estimate yet.

Question: is there another way to fix this problem? Can plumbers putty be used. Can you even get your hand in there?

Any help will be much appreciated. Thanks. vince

 

Did the mechanic inspect the vehicle? For it to be a cracked block it would have had to freeze with no antifreeze in the cooling system. If this were the case the radiator and heater core would probably break first.

It needs to be inspected closely. A leak at the rear of the block could be a freeze plug, intake manifold, heater hose or the heater core/pipe.

No, plumbers putty will not work. If it is a bad hose replace the hose. Bars leak makes some good stop leak products. I won't debate this as some people will say never use them as they will clog the system but I have never had this problem. Other people say it works fine. I used it in my daughters car for a cracked cylinder head and it held just fine for years untill we sold it. It will not fix all types of leaks or hose leaks however.

The best fix it to replace the leaking component. However depending on the value of the vehicle, how long you want to keep it and the cost of the repair you can decide if you want to try stop leak. Follow the directions if you decide to use it.

Also if one freeze plug is leaking others may be getting ready to leak. They usually leak because the cooling system was not maintained properly and what looks like mud builds up in the lower part of the water jacket against the freeze plugs and this causes them to rust out.

 

Take a mechanic's inspection mirror and a flashlight and look around at the rear of the engine for an intake manifold leak.

 

Another vote for the LIM (lower intake manifold) gasket. There are no freeze plugs on the back of the block. There are two freeze plugs on each side of the block. If it is running down the back of the block and not coming from hoses, etc, the only choice is the LIM gasket. Given the LIM gaskets poor design, that is the most likely cause.