I have a 95 Discovery with about 115k. It is having a problem with the coolant boiling out of the expansion tank.

About 6 months ago I blew the top radiator hose. So I replaced it, then about 2 months ago, I noticed that if I ran the AC, that the engine would run hot. Occasionally, I would have to turn on the heater and then the temp would go down to a normal level.

Then it started running hot in stop and go traffic (w/o the AC on).

I would fill the coolant to level (when cold). And then I would notice that coolant would spew out of the reservoir cap. Then it got so bad that the reservoir developed some leaks...

So today....

I replaced the t-stat, cleaned the front and back sides of the radiator (the front side had a ton of environmental debris, so I figured that was probably what was causing the running hot issue). swapped the coolant expansion reservoir with a known good one (from my other 95 discovery), flushed the radiator, filled with fresh coolant and bleed the system. Everything seemed good-to-go.

Took it for a 2 mile drive. Temp. stayed right were it should. Pull up in front of the house, and pop the hood. Coolant is steaming out of the reservoir, through the cap and also out of the sides of the coolant reservoir (just like the one previously had failed). The temp. guage was still showing that the temp was normal (I think because there was still enough coolant in the system).

The two electrical fans do come on when the A/C is on. And they were on, when I test drove it.

I pulled the radiators out of both of my discoveries and cleaned them out good. Tomorrow I am going to put in the know good one and see if that corrects the problem (although i need to wait until I get a new expansion reservoir since I have now toasted 2 of them).

Anyone have any other ideas about this??

Help!!! Please!!!

 

How about a new resevoir cap? The seal is on the cap.

 

Also, be very careful you are not overfilling!!

 

Hate to tell you but more than likely it is the head gasket.

 

The original black coolant tank on the D1s has been upgraded/replaced by a yellowish color tank because the original tanks would start leaking at the seams. Obviously you need to replace your coolant cap also. Have you had a radiator shop go through the radiator and rod it to make sure it's not clogged?

 

I did replace the cap. Or at least I pulled the cap from my other Discovery that isn't having a problem.

I am going to swap the radiator today and will order a new tank (and cap just to be sure).


Would a weak reservoir cause the steam issue? (not holding pressure?)

matt

 

Every time you repair something in the coolant system, you are supposed to bleed the system, are you?
I would go any have the system pressure tested and if need be do a chemical block test, in the mean time quit driving it or you'll be looking for an engine.

 

As long as you have the radiator out replace all of the other coolant hoses too.
You should always replace your coolant hoses at the same time and do this every 10 years no matter the miles.

 

Crap, my coolant resevoir is black...

 

Thanks.

I just replaced the radiator from my other discovery. Am going to put a fresh reservoir on and see if that makes any difference. And yes, I have been bleeding the system, religiously.

Yeah.. I will replace the coolant hoses when I can, I understand the need to replace them...

So, if the pressure test comes back positive what does that mean? If it comes back negative??


thanks
matt