So I purchased some Prestone Dexcool lastnight from Walmart lastnight. My question is, did I purchase the correct Dexcool by Prestone or am I looking for the Dexcool brand. I bought the higher end Prestone Dexcool, not the 50/50 mix brand of Dexcool that they had. I have just heard that Prestone mixed with Dexcool makes a pretty nasty mess. I have'nt used it yet I just wanted to get some information before I topped off the coolant tank.

The reason for this, is I have noticed that my expansion tank level is about 1'' below the cold mark. I have no leaks, water in oil, overheating issue, etc. But it seems every day there are more discussions over head gaskets, overheating & coolant issues. So I fiqure I would start with the small and work my way to the bigger problems if there are any. I would rather know now that Im loosing coolant and do a head gasket change than buying a new engine.

Just a question: Why does the Land Rover Discovery have these head gasket issues. Was it a poor design back in the day or what. I'm a fairly new owner of my Discovery so I dont know the history much.

 

As far as I know, Dexcool is Dexcool. I buy the full strength stuff and blend it to 50/50 because it's cheaper.

Some will argue that using Dexcool bad. I'm indifferent. It's supposedly a very long lasting coolant, but some reports have it eating gaskets and causing leaks. It's also known to leave a reddish resin behind where it leaks. Apparently, when it comes in contact with air it breaks down. Some people (although I'm not aware of any Disco owners reporting it) have problems with this gumming occuring inside hoses or elsewhere.

Provided that you change it every two years as directed by LR and take care of leaks right away, I don't see any with problem using it.

As to the head gaskets...I think we're all speculating on why they seem to fail. Some fail sooner than others. I started having leaks at 58,000 miles.

Could it be the Dexcool? Bad engine design? Short trips and frequent heat/cool cycles? I think it's a combination of all three.

 

The problem with dexcool is when is it exposed to O2 it sludges up on metal surfaces and inhibits heat transfer. That is why there have been troubles with dexcool especially in Land Rover all aluminum engines and radiators.

Regular Prestone Universal is a dexcool clone and can be added as a topoff fluid in a dexcool system. The prestone Dexcool is an actual dexcool clone without the universal ingredient. Dexcool is a very good long life coolant if you have no leaks, that is it is a terrible coolant for Disco engines.

 

So the Prestone Dexcool I bought from Walmart is not the correct coolant I'm looking for. I need to purchase the Dexcool brand then. Where will I find this particular Dexcool brand at?. What if one was to flush the entire system of the Disco with fresh water many times to evacuate the Dexcool and just go with a regular brand we have known to grow up with. Would it hurt the engine or does the Disco have to have the Dexcool brand. I'm thinking if it causes a break down in the head gaskets why keep using it, just use another brand that is not as harsh.

 

I just did my head gasket job and did NOT put DexCool back in. I have seen the red marks on the truck and on the driveway.

You should have seen what it did to the throttle body heater plate and its gasket. It looked like it was disintegrating.

 

If you have dex in your truck now then you have the correct coolant. Many of us have flushed out the dex and changed over to classic green, prestone/peak universal, G05 etc.

 

Prestone Dexcool is the same thing as Dexcool.

Prestone Universal is not dexcool but compatable if you need to top up.

 

All I know it is pink in the expansion tank.

 

that is dexcool

 

case closed.