Intermittent overheating issue- totally confused

[gips]

TBH its actually not about how old the parts are, but how many heat cycles they went through. For example my LS is 2000 and is still running all the plastic pipes from the factory . Its just the car was living in cold climate most of its life and is well under 100K km , which is around 60K miles. I already purchased some of the parts upfront and when the time comes i will probably manufacture most of the plastic tubes from aluminum and will buy some upgraded stuff from Jaguar.

 

[04_Sport_LS]

And I would have to disagree.

There was a member on here a year or more ago... that bought a Gen 1 LS with very low miles.

As he started driving it... the plastic parts in the cooling system started failing one after another. They failed due to AGE.

 

[gips]

And i would have to disagree.

Most likely the miles were not low as stated. The problem with plastic and rubber are the heatcycles . Both harden and get brittle from heatcycles. If there are no heatcycles the properties of the plastic and rubber do not deteriorate with age or at least not drastically to the point of failure. This is the reason plastic and rubber are pollutants number one on this planet , because of their properties. I am driving my car for over an year now ~1.5 years .There is not a single plastic part that has failed despite them being 23 years old and i expect this to keep up based on my driving for at least 3-4 more years. I do not expect any failure of plastic parts until the car gets to around 160K km , which is around 100K miles. Around that time i anticipate deterioration in the plastic will be enough for cracks to appears. Meantime , while on this topic. Does anyone know , if a company produces a cap for the expansion tank, which is rated less than 1.1bar . I am searching for a cap that hold pressure 0.9 bar like the ones on some japanese cars. If anyone is aware of a cap that has weaker spring let me know.

 

[gips]

For anyone interested i did find a cap that holds lower pressure than the original 1.1bar and fits the expansion tank of the LS. It seems the cap from ford F650 and F750 does fit and is rated lower. It is rated around 0.7bar . You have the option to buy locally in the US , because those cars were sold there. I got one form china as it was way cheaper to import one from there. This is what i got.

https://www.aliexpress.com/item/100....order_list.order_list_main.23.18b31802bBgnFK\

It fits and works fine. Spring is indeed a lot softer. I don't need to explain what could be the benefit of using one of those on a car with plastic stuff around the cooling system.

 

[joegr]

...

It fits and works fine. Spring is indeed a lot softer. I don't need to explain what could be the benefit of using one of those on a car with plastic stuff around the cooling system.

This disadvantage is that you might get more micro boiling of coolant in the cylinder heads...

 

[04_Sport_LS]

"You can lead a horse to water... but you can't make it drink."

 

[gips]

This disadvantage is that you might get more micro boiling of coolant in the cylinder heads...

Its highly unlikely to happen if you use good coolant. The boiling point of the water at 0.7 bar pressure is 112C. Using good coolant it raise up to 125C . Except in some kind of racing application i doubt you can achieve temperatures of over 125C of the coolant anywhere except maybe the oil spraying on the pistons themselves. But as i said this is , if anyone is interested . OEM the system works great, but for me its overpressurized in order to safely assume you can use plain water for cooling. If you don't do that you have a margin that you can safely use.

 

[04_Sport_LS]

That is absolutely incorrect. No modern engine cooling system is designed to run on water only... unless you are driving a Model A or Model T.

 

[04_Sport_LS]

And those antiques were designed to use a "drip system"... which meant constantly monitoring the coolant level... and refilling when necessary.

 

[gips]

And you think they will shoot themselves in the leg by providing a car that cannot cool on water in order for someone to quickly destroy it after the warranty expires? Then the whole world to understand their cars are trash and overheat like crazy 3 years after production ,around that time the warranty were around 3 years for most cars. I dont think anyone will will ever do this mistake, even if you put water in the LS now you can probably drive it for years until a problem occurs except in cold climates ofc.

 

[04_Sport_LS]

And you think they will shoot themselves in the leg by providing a car that cannot cool on water in order for someone to quickly destroy it after the warranty expires? Then the whole world to understand their cars are trash and overheat like crazy 3 years after production ,around that time the warranty were around 3 years for most cars. I dont think anyone will will ever do this mistake, even if you put water in the LS now you can probably drive it for years until a problem occurs except in cold climates ofc.

 

[TheDude]

If there's zero lose of coolant, it's unlikely that air is getting in somewhere. Generally speaking, if air is getting in somewhere due to a crack, loose cap or loose clap, coolant will be exiting in kind.

 

[joegr]

If there's zero lose of coolant, it's unlikely that air is getting in somewhere. Generally speaking, if air is getting in somewhere due to a crack, loose cap or loose clap, coolant will be exiting in kind.

It just seems like there is no coolant loss, but there really is. Air displaces it, so the level stays the same. A small amount of coolant seeps out the micro cracks and dries on the outside of the plastic parts. If you know what to look for, it is very obvious. If you don't, then it just looks like a dusty engine bay. A lot of people seems to think that no puddle under the car = no leaking.

 

[04_Sport_LS]

@gips

Not to mention that 125c (257f) is going to torch the aluminum heads.

That's why if the engine temp hits 250f the "red light of death" comes on, and you get a warning on the message center.

Try it... I'll bet you start dropping valve seats.

 

[gips]

I have been driving like this for like 10K kilometers now . As i said i prefer less pressure in the cooling system. I didnt say no pressure i say less pressure. Plain water at 1.1bar has the same boiling temperature as 60% antifreeze at 0.6bar, so running good coolant at lower pressure does not have any negative impact on the system, but it will give you some extra miles on the plastic coolant parts. I am running some of my older japanese cars at 0.5bar for ages on the factory coolant hoses 30+ years old. I try to find low pressure caps for all my cars, but for some of them there is simply no such product or is long sold.

 

[04_Sport_LS]

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