Which Coolant is Best?

They are just ethylene glycol and distilled water. No difference in quality, IMO, kinda like buying table salt. With coolant, getting it replaced once every year or two is far more important than the brand. Maybe have it flushed if it hasn't been done for a while.

Dave

I have a '96 i30 and it's time to change the coolant. I bought this used two years ago and it had just been serviced at an Infiniti dealer with new coolant. Based on the cost on the receipt, I hope that it was Nissan OEM coolant.

I checked with the local Nissan dealer and they claim their service department uses the standard green Prestone rather than the Nissan fluid to save their customers money.

What are your opinions?

Thanks,

Keith

I have a '96 i30 and it's time to change the coolant. I bought this used two years ago and it had just been serviced at an Infiniti dealer with new coolant. Based on the cost on the receipt, I hope that it was Nissan OEM coolant.

I checked with the local Nissan dealer and they claim their service department uses the standard green Prestone rather than the Nissan fluid to save their customers money.

What are your opinions?

Thanks,

Keith

Nissan pumps are tougher than, say, Honda, and can tolerate silicone-silicate coolant. It is NOT a great idea, however, and probably will shorten the life of the pump. Infiniti charged me $628.00 a few weeks ago to replace the pump on my '96 I30t, by the way. And it was out of service for 3 days.

Silicate free is the way to go. I changed the factory coolant at

37,000 miles and used Dex-Cool. Pump failed at 95,000 miles. Not a great showing overall, but reasonable. Did the Dex-Cool cause the failure? I doubt it.

The Infiniti dealer said Dex-Cool is acceptable. Of course, like the dealers using Prestone (green), they stand to make money in the long run no matter what.

I would flush the Prestone out at your early convenience, and replace it with Dex-Cool or Nissan coolant. Flush it out really well, not just a radiator drain-and-fill. Otherwise, the Dex-Cool will react with the Prestone and either gum up or cut the coolant life to 2 years. And continued wear will result if there is any silicate left in the system, too.

JM

95K out of a water pump is quite good. I replace mine every 60K when I do the timing belt.

Bill G '91 SE Auto

165K miles

I'd stress to be sure to flush the Prestone really REALLY well if changing to the Dex-cool, otherwise you'll need to change again in a year or so. If another antifreeze contaminates Dex-cool, especially silicate type, the long life of Dexcool is lost.

When done right, Dexcool will easily give great corrosion protection for 5 years or more in a Max's all-aluminum cooling system.

BuddyWh

While that is certainly true about the glycol (actually an anti-freeze and anti-boilover, calling it a coolant is a misnomer), it's not true of the anti-corrosive package. There are several different types, with their own advantages and disadvantages.

In general it's a good idea to stay away from high silicate formulation anti-freezes (Prestone) in Japanese autos which come with high nitrate and phosphate formulations.

Probably the best, especially for all-aluminum cooling systems, are OAT formulations (like Dex-cool) but a vehicle has to carefully changed over to it. Done right, it lasts for a long time... actually much longer than the 5 years recommended. Hybrids (like many European) are easy to change to, but do not push them beyond their recommended change intervals.

At least from what I've read...

Buddy

My concerns about Dexcool arise from all the problems GM owners are experiencing when the stuff turns into mud in their engine. I don't know whether they don't change it at appropriate intervals but I believe they advertise it should last 5 yrs/100k ? I'd rather change my coolant more frequently with the regular green Prestone. Which coolants don't have silicates in them? I'm aware of OEM Toyota Red, OEM Honda, Dexcool?? and I believe there might be others.

I have read the problems GM had with Dexcool... an OAT formulation... were with cast iron block engines. If the cooling system is allowed to run low for long periods of time a sludge forms from iron surfaces in the vapor zone, i.e., not in constant contact with liquid antifreeze. The sludge builds up in heater cores and engine passages. This was compounded by a radiator cap that easily plugged and, among other things, wouldn't draw back the overflow so that a casual check of the overflow tank would make you think the system was topped up.

Their 4.3L V6 was especially prone because it had passages real high on the engine compared to the radiator, so if the level is even a little low sludge could form.

Another problem occurs when large quantities of silicate antifreeze are mixed with Dexcool for long periods( years) in the system. The silicates can fall out of suspension over time forming a jelly. That's rare though and easily controlled.... first, make sure you flush well at change over, or change it again in a year (as you should anyway if NOT using an extended life antifreeze). Finally, even half decent shops now recognize the orange color of Dexcool and use the correct top off.

AFAIK, all Japanese coolants are low in silicates. Several European mfr's use a hybrid coolant (OAT and phospate or somesuch) making them both low silicate and extended drain. However, most shops do not recognize or stock all the myriad of colors... blue, pink, yellow, tangerine, etc, so you'll never be sure unless you always carry some with you.

Finally... in several articles I've read, OAT antifreezes performed as well as high silicate formulations in all aluminum systems, it lasts for a long time... actually much longer than the 5 years indicated... and doesn't pose the risk to water pump seals. I use OAT, but only when I know i can get a good flush first. But I'll never again use Prestone in my Japanese car... it's either OAT or a Japanese formulation.

BuddyWh

I agree. Regular antifreeze has worked just fine for decades with regular change intervals.

You realize many Japanese cars still use cast iron blocks...

The "mud" comes from contamination. Either the old-type coolant didn't get flushed out well, or else the level of Dex-Cool dropped too low, and air got into the radiator for an extended period of time. Texaco recommends you overfill the coolant bottle to the extent practical. You also should remove the radiator cap (with the engine cold) and visually check to see that the radiator is completely full.

I have seen photos of the orange mud created when air gets into the system. I doubt that the radiator can even be rodded out; it looks like a replacement would be necessary. And of course getting the mud out of the engine itself is just about impossible.

Dex-Cool is long life stuff, but is not "maintenance free", in that you must keep an eye on the coolant level.

JM

Sounds like way more trouble than it's worth. Doing a drain and fill every couple of years isn't that big a deal with none of these headaches.

Because I'm not one to ignore service on the cooling system.... allowing it to run low for years at a time... I'd still use Dexcool without worry. Considering it's long service life, OAT is the best anti-corrosive going.

But if one is worried... they could still change it on the same schedule as a silicate and completely avoid any possibility of problems with water pump seals. Since it's cost is about the same as Prestone they should spend no more. As it relates to the Japanese coolants, the anti-corrosive is far superior and it's cost is a lot less.

But at any rate I'll never use... nor suggest using... a high silicate (Prestone) in a Japanese car. Cast iron block or not. That is something I've had my own experiences with in three Hondas and an Isuzu.

BuddyWh

Hello Folks,

I need help.

I bought my 2002 GLE in 11/2002. It already had 968miles on it when I bought it. I have noticed rust spots (mainly on the left side) in the inside roofing on the carpeting--from the driver side sun visor all over to the rear section on top of the left back seat.

I took it to the dealer's service people just yesterday. The lady told me it was not rust but soda spills. Beyond the patronizing and insulting response (I have observed and checked these spots for over a year), they simply attempted a cosmetic fix--brushing or polishing over the spots. The spots are back with a vengeance.

Please advise, suggest and counsel. What recourse do I have? The odometer now reads 26,180 miles.

I appreciate all input.

'BioDun J. Ogundayo, Ph.D

Having just purchased a couple bottles for use in my Max, I wondered the same thing. The generic coolant I bought contained ethylene glycol, diethylene glycol, and distilled water. A look around the Autozone showed others with these three ingredients plus silcone silicate, and others. I concluded that if silicone silicate isn't in the content list, it's safe.

Dave

Zerex G-05 is low phosphate, low silicate, but not NO silicate at around 250 parts/million. It is "hybrid organic acid technology" (HOAT), FWIW. It's compatible with 'regular' anti-freeze, but the manufacturer (Valvoline) recommends a good flush and a clean system if converting over to it. It usually says "Ford/Chrysler compatible" on the bottle.