Coolant change on 98 Max

Any suggestions on the best type of coolant to use in the 'VQ' engine? I have seen both the 'old' Ethylene Glycol coolant and the newer 'Mono Propylene Glycol' antifreeze - the 'new' stuff is claimed to last longer and prevent corrosion better than the traditional stuff. Any thoughts or experiences regarding this?

Also - any suggestions as to the best way to reach the block drain plugs? - they don't look easy...

Eric

Reply to
Eric
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Do not use traditional antifreeze. Either use Nissan antifreeze or use Valvoline G-05 or Mercedes antifreeze. Ford and Chrysler also have the proper stuff as long as you get the latest G-05 equivalent. Traditional Prestone type antifreeze uses high amounts of silicates for the anti- corrosion and will (eventually) cause water pump problems.

Reply to
'nuther Bob

go to the dealership and get Nissan OEM coolant, a gallon runs about 13.00$

and what ever you do DO NOT use Dex-Cool coolant

Reply to
NissTech

Dexcool got a bad reputation when it first came out due to poor serviceing and owner neglect, unfortunate side effects of a 5 year maintenance interval for this antifreeze. If you keep your system topped and don't mix chemistries you will have the best anti-corrosion protection possible.

The bed rep originated from a combination of design issues and service departments learning how to cope with a new technology. A sludge could form in cast iron block engines that plugged heater cores and radiators, sometimes even engine passages. It can happen when the system is ignored for long periods, levels get low and the cast iron block is allowed to rust in the moist environment.

GM's 4.3l V6 had a special problem, IIRC, because it had passages that weren't permanently submerged even when the system was full.

There is also a potential problem when mixed with silicate antifreezes in high ratios.... the silicates can fall out of solution forming a jelly like contaminant.

Service departments are much smarter now, I've noticed. They all have Dexcool antifreeze available (it's the orange colored stuff). Even so, I always make sure they know it when I take my vehicle in for service.

I like the idea it is widely available so I don't have to carry a jug of antifreeze with me on trips or, worse, top with a silicate antifreeze.

Since problems only occur when the system is poorly maintained for extended periods I could still benefit from it's superior anti-corrosion protection and change on an annual or bi-annual cycle as with any other antifreeze and completely avoid any possible problems.

Also, Ford discourages it (or any other non-silicate AF) for some of their models. They maintain a silicate antifreeze is required in these models to prevent water pump impeller erosion due to cavitation. A silicate chemistry works by continuously depositing a silicate layer on the blades that prevents erosion.

BuddyWh

Reply to
BuddyWh

Propylene glycol is usually marketed as a "Green" product because it is LESS poisonous than ethylene glycol AF. It's still poisonous, though.

The glycol (either type) are the anti-freeze, not the anti-corrosion protection. They both last essentially forever as an anti-freeze, so I have no idea why anyone would make a claim of "last's longer" or "prevents corrosion better".

What is the anti-corrosion chemistry it is using? That's what determines those characteristics of an anti-freeze product.

Be interesting to know what the 'mono' part means, though. Any chemists to help explain that and it's significance?

BuddyWh

Reply to
BuddyWh

There's a great deal of argument on that. GM claims that the problems were due to folks letting their systems run low. (I might suggest that a coolant that cannot tolerate a little air in the system is a problem to start with). Other problems (cited by GM) include an incompatibility with a sealer that GM adds to many engines at the factory, issues with solder leftovers, etc. Other folks claim that Dexcool itself is to blame with too many contaminants getting into the product at the (chemical) plant. GM has a *lot* of money riding on the issue including potential repairs to hundreds of thousand of cars so they are trying hard to limit their exposure. FWIW, two year old cars are showing corrosion problems.

With all those issues concerning "contamination", I can't see how you could ever get an existing cooling system clean enough to convert to Dexcool. If I had it in my car, I'd replace it.

Watch out for color use. It is no longer definitive. Bob

Reply to
Bobert

Talk to Valvoline. They candidly discuss the tests they did, the tests GM did, etc. Note that GM is changing to a Valvoline based version of "Dexcool" this year. Note that it's the same type of OAT coolant. Think about that for a minute.

Evidently not. OAT problems such as those you mentioned are possibly still an issue.

See above: keep a watch. Texaco Dexcool is out.

Bob

Reply to
'nuther Bob

So the concern is GM's _Dexcool_? as opposed to the compatibles... made by Prestone, Texaco, Zerex/Valvoline and all using the long-life OAT chemistry.

That's what I'm looking for anyway, even if I change earlier than the

5/150 interval recommended. Very good aluminum protection without silicates. The G-05 hybrids use OAT inhibitors but also advertise "low silicate" not "silicate free" required for Japanese cars. It seems the primary goal is phosphate free, required for European autos.

I've always used Texaco's Halvoline Dexcool compatable... mainly because it's sold at the local PepBoys :-)... ever since I learned about it and researched Dexcool's early issues. But you say Texaco sells a Dexcool branded coolant now? So GM is licensing the name? I didn't see it on Texaco's web site yet... I'll look out for it.

BuddyWh

Reply to
BuddyWh

That's the way I hear it. Note that your cooling system needs to be _very_ clean to switch to OAT coolants and to not get corrosion. It's not necessarily the OATs that are the problem, just the formulation that GM uses and/or contamination problems with it. Also, not all OAT based products are the same. That is, there can still be a large variation in the coolant regardless of the fact that it uses OATs. If you use OATs, keep a close eye out for any corrosion.

From what I hear (seat of the pants) if you change every 2 years then you should be OK.

I don't think Nissan's coolant is silicate free, just _low_ silicate. I say that without having an actual % analysis or MSDS on hand. If you know where one can be located, I'd like to read it.

I know that the G-05 has a low amount of silicate for aluminum protection. That's the compromise you have to make to get the protection without OAT, AFAIK. This is not the same as Prestone green, which prides itself on having a _high_ silicate level. That was Prestones innovation in the 70's that reduced corrosion in cooling systems. The Europeans have been using aluminum and (worse) mixed iron/alluminum engines for many years with G-05 type coolants.

GM buys Dexcool in 45 gallon drums from Texaco... It's probably shipped in tail cars to the factory. I dunno. I imagine that what they sell at the GM store says GM on it. You might want to check into the Valvoline G30, I think that's what they will be selling as their OAT product.

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Reply to
'nuther Bob

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