I've been fighting a "low coolant level" indicator issue. Twice I've had the gaskets replaced on the thermostat housing and the O rings. I've replaced the crossover pipes and had the gasket on the water pump inspected. Yet, again today, the "low coolant level" alert came on --- BUT ONLY FOR A WHILE.

Now my mechanic suspects the float is sticking.

Here's my question: the "orange" coolant, specified on the reservior was replaced by the mechanic with green coolant. I asked about it. He said the coolant he used is formulated for high-performance cars.

So, as far as my (possibly) sticking float goes, does it make a difference whether the "high performance green coolant" or the recommended long-life orange coolant is used???

 

Despite about 10k words on this subject, the type of coolant makes absolutely no difference in the 'low coolant' situation.

The float has a magnet that closes an isolated from the coolant, glass encapsulated micro switch. The float will float in any liquid from antifreeze/water to a warm milk shake.

The micro switch can fail, or the electrical connections can corrode but there is no magic here. The micro switch is easily replaceable but impossible to obtain unless you have a relative in the recycling business.

The only issue is that the newer organic coolants can be non compatible and cause problems.

 

Al, your mechanic is right and there is an old factory bulletin which explains why. If the reservoir is chock full of coolant and the warning light on, you'll likely need a new reservoir.

Tom, to the best of my knowledge your first statement is correct. And I don't have proof of the last statement, but I follow it as good practice and eliminate the concern.

 

I'd be more concerned that my mechanic mixed coolant types - that's not a good thing at all!

Like everything else coolant is more complex than before - specific types for specific engine compositions and can't be intermixed.

A very important role of antifreeze is to prevent electrolysis. Electrolysis occurs when 2 or more dissamiliar metals come in contact and begin exchanging electrons thus creating corrosion.

My tractor engine is primarily cast iron and dosen't need much help except from freezing. My XK8 (and virtually all modern engines) are combinatoins of aluminium, copper, steel, exotic alloys and iron. It needs the right type of coolant to prevent internal corrosion.

Interestingly, as the anti-corrosion additives are depleted the old coolant actually becomes a pretty good electrical conductor - actually accelerating the internal corrosion process!

These days you should check your antifreeze two ways - with an "old school" tester to measure it's ability to protect from freezing AND with a multi tester to check it's insulating properties.

To test the insulating properties do this:

With a cold engine remove the radiator cap and warm the engine. Set your digital multi meter to DC volts at 20 volts or less. When the engine reached operating tempreture and the coolant is flowing, put the POSITIVE probe directly into the coolant. Put the NEGATIVE probe on the negative battery terminal. Good coolant reads .4 volts or less. Tired coolant reads .4 or greater - replace it.

 

EXCELLENT INFORMATION ! ! !

I understand electrolysis but had never associated it with antifreeze. My 5 year old Ford car with 115k miles measured, after stabilization, 0.315v but initially was at 0.425v. That is a warm engine not running.

Coincidentally, had just purchased a couple gallons of Zerex G05 to replace the coolant.

 

I say yes it makes a difference. I changed out a water pump in my Vette. I replaced the OEM pump with Edlebrocks (spelling??) top of the line pump. I flushed out the system with water and changed from the green stuff to the orange stuff thinking I was doing a good thing adding the top of the line coolant to my system.

A year later I had to replace both the water pump and the radiator. The metal got weak in the radiator (eaten up) and the same for the water pump causing the pump seal to fail.

I replace both and flushed the system again and went back to the green stuff and I've never had a problems since. That was 11 years ago.

I've read several articals about both types of coolant and you don't mix them. In my case I'll never switch from one to the other thinking I'm doing a good thing, I can't afford the parts replacement costs!!

If the cap and your docs say to use the orange stuff then don't mess around, use the orange stuff. If you have green stuff in it now, dump it, flush your system and put in the orange stuff.

Also keep everything full, topped off. DEX Cool (GM's name for their orange stuff) from a couple of articals that I've read on the subject, will cause sludge in your radiator if it is in constant contact with air. It will eat metal too under this condition. Do a web search on the subject.

Just my $.02

 

I often see posts looking for and or suggesting alternative replacement fluids. I never understood why when the factory recommended is available for purchase. Now this post had a lot of meat to it and I must say it appears that everyone is on the right page by asking questions. Making changes without research can offset the savings you are looking for. Thank You! I enjoyed everyone’s $.02. Great post!

 

C'mon Gus, what fun is that? If people stuck to factual information, most of these forums would be nearly empty. Think about all the great archives we get to muddle through, and how much more fun it is to complicate basic issues.

 

You got it! One of the reasons I put all my info in one place.

 

Gonna do this tonight, never knew how to check it, until now. Thanks!

 

I'd like to take credit for being real smart all these years but, in fact, I just learned about testing coolant with a multi meter. From a Home Hanydman type magazine no less!

 

I want to flush and replace the antifreeze in my XK8. Where is the radiator drain plug? Thanks in advance.

 

The lower right corner of the radiator. That is if the driver is on the left. You will need a short screwdriver with a wide tip. Check the hoses and change if necessary.

 

What is the recommended coolant for a 2002 xk8? I used dex cool orange but was told that company was sued for some reason and not to use it.
What type should i use?

Incase my coolant was mixed by jiffy boob, should i use a chemical when flushing?

And last, I just undo the plug and turn on the garden hose to flush it?

I dont think ive ever done a coolant change on this car and i've had it since 04. Please help!!

 

also i have a bad lower radiator hose, i should replace this before doing the flush im guessing?

Do i use regular clamps to replace?

 

Changing out an unknown antifreeze I would take a little time to drain/refill with water, warm engine, drain/refill, warm engine cycles to get out all of the old coolant as possible.

All the new, long life coolants are classified as organic. There is OAT and HOAT and they are reported to not mix well. I do not understand all I think I know about that subject. Do a Google on the above acronyms and you too can understand about coolants.

Ford goes with G05, GM goes with DexCool. Jaguar calls for DexCool but was owned by Ford for 20 years.

There, now you have your answer. Long day, too many olives.

. . . . and yes, you need to use standard old screw type clamps on the lower radiator hose. You will never be able to get the OEM spring clamps back on . . . I promise.

 

Thanks!! I like your blue!

 

If you go over to the Prestone site and look up their 5/100,000 Extended Life coolant (Green) you'll see that it can be mixed with Dex-Cool products (Orange). Their extended life products are GM certified as Dex Cool compliant.

Now, they also make a Dex Cool 5/100,000 product as well. That's sort of confusing to me.

I had the Jag drained when I realized that what I had on hand was 5/100,000 Extended Life green - so I went ahead and used it. For my Corvette I stayed "orange to orange".

By the way, draining the radiator and hoses only dropped about a gallon of fluid. The system holds 10 quarts I think, so beware if you do a flush - there's a lot of fluid left behind.

 

What i ended up buying was Peak Global Lifetime because it met the jaguar specs.

Now to get this right, do i refill it with just this 50/50 mixture? 5 liters of this and no actual water since its pre diluted?

 

Ok i put the right amount of everything in.

In the process of flushing the system, a hose port on the coolant expansion tank broke. I noticed then that the dex cool had eatten away at it and it was corroded all the way through (just the port). It has a second unused port next to it. I drilled it out, plugged the other with a screw and then accidently broke the one pointing towards the back. I drilled this one out too and used a pipe fitting part from ace hardware and put it all back together. I think its stronger now than before. And i saved $250 from a new one. The only problem is that the device inside that reads how muchj coolant is there was corroded too and came out in pieces, so now my low coolant light stays on ( any simple fix for this?)

The good news is that after this all, my car runs much cooler than it had before. In the past when getting out of the car you could feel a horrible amount of heat coming from the engine. It didnt do that today, and its 90 outside. Think there is a chance that there was damage done by the heat (besides needing new tensioners)?? Im wondering if i should get my engine checked for cracks now. The car is at 100k miles, but id like to make it last another 100k.