Hey everyone. This is our first post, but my girlfriend and I have been active readers of the site for some time. We have found it especially helpful in the few repairs we have done so far.

Anyway, we have a fairly straightforward, if bizarre, question for you experts. My question: Can a cooling system that was leaky but did not have any overheating problems suddenly start overheating when the leak is plugged?

I am providing some background info below.

We have a 2001 Disco II with 134k miles. It has been having some of the typical cooling issues as of late (needs a quart of coolant every couple of weeks, gurgling noise, etc). Anyway, my girlfriend brought it in to a mom and pop shop here in Atlanta a few weeks back to get the heating issues fixed. The shop replaced a lot of components in the cooling system, including the head gasket. They did not replace the radiator because this was replaced by the same shop a year ago. I was not involved at this step.

The shop called us this week and claim that the system no longer has any leaks, but the year old radiator must be replaced because it is clogged and causing the system to overheat. They say they found some stop-leak residue in it and that must be causing the leak. I have no idea where the stop leak came from as the radiator is only a year old and the only person to open the hood over the past year just changed the oil. But, the stop leak is beside the point. I am confused as to how the system is suddenly rapidly overheating when it didnt before.

My question: Can a cooling system that was leaky but did not have any overheating problems suddenly start overheating when the leak is plugged? I have a sneaking suspicion that the mechanic is making up the stop leak situation, and the new overheating problem was caused by something they messed up when making the most recent head gasket repair (or there is a stop-leak clog, but it was caused by the mechanic when he or she was trying to fix this issue last week). I cant possibly figure out how a system that didnt have any overheating problems before (it just required coolant to be added periodically) suddenly starts overheating once its leaks had been plugged. A newly pressurized system wouldn't cause this right? Am I missing something?

 

I bet they didn't bleed the system correctly. I smell a gutter rat.

 

Where was it leaking?

 

They claimed head gasket, but I did not personally verify it. I didn't get involved until today (my girl friend was handling it before, and she approved the repair). I assume they pressure tested it. I know the head gasket is especially common with Disco IIs.

 

I run into alot of mechanics that assume a part is bad based on the history of certain vehicles. They will not confirm a bad part, just replace the suspected, untested part and when that doesn't fix the problem, they claim there were other problems. I detest mechanics that throw parts without verifying the part is wrong(or at least being justifiably suspicious).
Always ask to see the bad parts they removed.

That being said, unless they put stop-leak in the coolant when they changed the radiator, ask your girl friend(nicely, of course) if she or a friend put it in.

 

i would pull the radiator and bring it to a radiator shop. time to get a second opinion to see if you are being fed the barn leftovers.