4.0l XJ overheating? Start here - the basics!

[Rodgebone]

actually in hindsight i'm being premature about switching to pre-mix. if its formulated as concentrate then it should have the appropriate amount of additives to mix with distilled water to 50/50 or 30/70 or whatever the label calls for. so im gonna flip flop back

[SJCXJeep]

Originally Posted by XJeepers

Personally I have always used concentrate for the same reason. This time it was the castrol, but I have used tectaloy and others for my other cars without any complaints.

I too use concentrate, rather than pre mix... Usally its Nulon or Tectaloy, as you mention... cheaper that way, plus was always concerned on how good the pre mix product is... ?

[carvesdodo]

Originally Posted by Rodgebone

actually in hindsight i'm being premature about switching to pre-mix. if its formulated as concentrate then it should have the appropriate amount of additives to mix with distilled water to 50/50 or 30/70 or whatever the label calls for. so im gonna flip flop back

Good being able to thrash stuff out on an open forum huh

Personally I dont think theres a great deal of difference in the additive amounts in either a bottle of 50/50 concentrate or a 30/70 one but users should be aware there is.

Only real reason I use a premix is so that I can go anywhere and still be able to find the cheap, commonly available, one I use .... at almost any town with a halfarsed autoshop .... and not have to turn hicksville upside down hoping to find that "special" brand and a coupla bottles of distilled water.

[josh9465]

so in Aust where the temps are warmer, its better to use a 30/70 coolant? i think i get that.

i gather water is better at absorbing heat than pure 100% eth-glycol???

so what coolant brands at 30% do you recommend to use in the 4.0L carves?

cheap and nasty, expensive or mediocre?

Originally Posted by carvesdodo

Good point Rodge .....

Generally the mix is referred to as eth-gly/water .... so 30/70 is 30% eth-gly.

But it only needs to be written or referred to once ... in the reverse - and its all out the window.

The ratio numbers have no real reference to the anti-corrosive additives, coz thats measured in teaspoons/tablespoons/whatever .... per litre of mix .... regardless what the mix ratio is.

Which coolant grade to use ... and even which type is a drivers choice depending on what they know or whether they are warranty bound.

There is 4 sources of anti-freeze mix info ... Ooooops ... 5 sources ... thanks Nakkas ...

First is all the knowledge, beliefs, experience, opinions, facts AND fairy tales on car forums,
Second is the "our coolant is special" drivel from the car manufacturers,
Third is what the "coolant" manufacturers will tell you before getting to the point of upsetting the carmakers,
Fourthly there is the coolant scientific community ... who dont seem to give a toss who they upset when quoting facts and figures ... Coz they are always right ...
And lastly there is all those unchallangeable private websites with all their right AND wrong info.

I like to jumble it all together for a balanced view ....

[murray]

guys only prob i can see with diluted mix is the temps that engine runs at you could suffer explosive errosion on the the block barrel area
due to surface cavitation as coolant has a lower boil point
basic physics on latent heat point to boiling point is only 1 deg
now i am not saying cooling system boiling point but the area of interaction between coolant and barrell area
on the desiel these are wet liners i run cat elc 50/50 premix
and have no probs
the other thing regardless of brand pre mix is ready to go for a trail top up

[carvesdodo]

Originally Posted by josh9465

so in Aust where the temps are warmer, its better to use a 30/70 coolant? i think i get that.

i gather water is better at absorbing heat than pure 100% eth-glycol???

so what coolant brands at 30% do you recommend to use in the 4.0L carves?

cheap and nasty, expensive or mediocre?

Eth-Gly in addition to being an anti-freeze ... is a heat transferring item ... not so much a cooling product ... Gathers heat OK ... but needs a damned good heat exhanger unit (radiator) to lose the heat ...
Dont even mention using 100% eth-gly
60/40 Eth-Gly/Water ... is the max even chrysler recommends .... and is most useful for when on a polar bear hunt ....

30/70 will give you a slight gain, as will a slightly lower thermostat rating and a better fanclutch etc. Its all dependant on how you approach your cooling system.

Gotta remember - A jeep ... or any other vehicle ... doesnt have a radiator, fanclutch or coolant etc ... It has a "cooling system" ... and the cooling system has a radiator, fanclutch, coolant etc.

Overall benefit is a mild combination of things rather than looking for a major "fix" with just one item.

I recommend a quality known brand with aust std ratings and the additives your vehicle needs .... and would be very shy on a Crazy Clarks special or any other mix offering miracle overheating cures

For my own personal use ... I just use the tectaloy 60plus "type B" 10/90 mix and change it every 12mnths. Using a fancy 5yr longlife coolant to keep the ecofreaks happy doesnt rattle my chains ... But "type B" is not ideal if you have a heap of aluminium bits tho.

If I was spending some time down the snowy I would run a 30/70 ... even though I never used anti-freeze when I lived down there and the HR was a new holden release ...... I'd reckon a 30/70 mix in the Valvoline G-05 ( http://www.valvoline.com.au/files/productpdfs/52.pdf ) would probably be pretty good. G-05 is pretty much the formulae Mercedes has been using for donkeys ages apparrently ... and the other coolant brands have their versions.

With Rodges permission I might provide a bunch of eth-gly/water mix characteristics and the original tech site link in a later post ..... but I need to lay it out so that the individual bits of info arent misconstrued ...

So PM, post example, heading your way for approval in a few days Rodge.

[XJeepers]

Whilst you are lowering the boiling point by a few degrees, you are also lowering running temps few degrees as well.

30/70 = 105 degrees boiling point
50/50 = 107 degrees boiling point

This is unpressurised, so the 16psi in the sytem will raise this a few more degrees in both instances by 5 degress (IIRC). I don't know about the diesel, but that is redline on the petrol. Something else is wrong if you are hitting the redline on the temp (in any vehicle) in my experience.

When I was running 50/50, my system would often go just past 100 degrees.

Running 30/70, the first thing I noticed was that the system was running only a couple of degrees cooler, but the big thing I noticed was it spent less time at the 100 degree point. I didn't expect this last point, but it stands to reason that if the system has more water, it will be more efficient in sheding the heat.

Either mix is good in my opinion. I just think (at the moment anyway) that 30/70 in a healthy system seems to work well in my experience.