[jthomson]

Erring on the side of 'fix it before it breaks', how often should hoses be replaced on a daily driver, non-tracked car? Especially radiator hoses. Thoughts?

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[MCL968]

Squeeze them, if they are spongy or crunchy replace them.

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[Rap]

I second that. I almost paid the price for that last year.

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[Roboman]

If it is peace of mind you are looking for then replace on an annual basis the main hoses (top/bottom) as they carry the highest volume and pressure; maybe say just before your service. These hoses have the potential of causing the greatest damage in the shortest time if they rupture. While you're doing that you will naturally examine the smaller hoses, looking for puffiness around the hose clips, discoloration from leaks, crunchiness etc. as recommended above by mcl968 and rap. Such frequency is probably not necessary (don't know your commute distance), but for such minimal expense and peace of mind, why wait?

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[Waylander]

The hoses should last at least 15-20 years, a full engine set is about 400 dollars


All the hoses are at the same pressure 15psi, that is controlled by the coolant tank cap, this should be replaced more often, at least once every 5 years

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[jthomson]

Thanks all.

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[Roboman]

Later I'm going to engage in a deeper conversation about the same pressure throughout the cooling system, as I believe there must be an instantaneous higher pressure on the "up stream" of the water pump. It is normally (I believe) the top hose that fails catastrophically, and so I feel that is indicative of the higher pressure. I'm hoping we have some engine designers/testers in our group who can cast some light on what is happening, and hence where one should be vigilant. But right now I have other things to do .....

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[MCL968]

That is an interesting question, and it was why for many years one of the originators of this forum advocated for drilling three 5/32 holes (as I recall) in the thermostat to allow some coolant movement prior to the opening of the thermostat. Mine has been drilled for years, and there have been no ill effects except for a more gradual temperature change as the thermostat opens and closes.

 

Racers have done this for decades to minimize thermal shock, but streetable cars may have less of a need to do so. Still, I consider it a possible positive without any real negatives so I continue to do so, even though I tend to drive like a myopic pastor in the rain.

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[Roboman]

MCL968 - great thinking outside the box, and drilling those holes will partly reduce the instantaneous pressure build up under acceleration when the engine is cold. By "racers" do you mean Porsche racers, or is this common in the general racing fraternity?


Do we have any failure analysis ????? Mean time between failure of various hoses? Mean time of failure after start-up, i.e. typical temperature of engine/was the thermostat open or closed at hose failure?

I shall go online and ask the question, but I'm not expecting to find an evidence-based answer.

More later

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[Roboman]

JT .... I've not found the evidenced data I was looking for, however this article seems quite balanced and suggests 10 years / 100k miles as a change interval.


https://www.carid.com/articles/when-is-i...hoses.html


And then there's this ..... MX missile review in congress where someone just happened to use radiator hoses as an analogy for mean time between failure .... heady stuff!!


https://books.google.fr/books?id=4LkfAAA...AAegQICRAB

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[Roboman]

Okay something of interest......  I joined JSTOR so I could search technical research, and found

 

"Performance Studies of Ethylene-Propylene Rubber Automotive Coolant Hoses .... 1990"

 

Unfortunately they protect their publications so I couldn't cut and paste relevant sections of the article.  However, I took a screen-shot of the conclusions page, see below, I hope it will be readable once it's attached.

 

There's no mean-time-between-failure info., however it does point to micro-electrical currents as being a major contributor to the degradation of the hose walls.  I've previously read about electrical currents in coolant but was not aware of the significance.  What is being suggested in this article is that changing the coolant at regular intervals is a good idea as it removes the build-up of metal particulates in the coolant, the cleaner coolant provides less opportunity for the electrical currents, and hence the degrading of the hose is slower. (please don't ask me what that change interval should be    )

 

   

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[Waylander]

The change for me is when they leak, but I went blue Silicone this time

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[snova]

about to change coolant.  Any recommendations as to which one to buy?

TIA

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[ds968]

about to change coolant.  Any recommendations as to which one to buy?

TIA

 

Prestone Orange  has worked well for me .  (  Phosphate-Free  is a must ) 

I would also recommend adding a bottle of Water Wetter solution in there, it helps reduce and maintain a lower coolant temperature.  

 

p.s. Haven’t changed hoses yet,  25 years, 125,000 miles.  They may degrade from the inside, but how long that takes is a mystery, the ones in my car look very good and feel perfectly fine to the touch / squeeze.  

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[snova]

thanks for the tip ds968.  Will do.

 

also wondering if I should replace the thermostat. No idea when it was changed last.  

They seem relatively cheap.  However, seems like I may need some kind of spanner tool to get it out?

Also not sure what other gaskets or o-rings I should change if I decide to swap it.   Would appreciate any pointers and recommendations.

 

sounds like I should also swap out the coolant cap while I am at it.  Thanks for the tip Waylander.    At times I feel like I am slowing replacing the entire car. piece by piece.  :wacko:

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[Waylander]

The Porsche manual recommends G48 which is the BASF formulation for antifreeze for alusil blocks

 

that is what I use in my car,

 

but I think most antifreeze is now ok as tech has moved on in 30 years

to change the stat you will need a set of 90 degree large internal circling pliers, mind you don’t pinch your fingers, as it’s hard to see what your doing

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[snova]

Thanks Waylander.  You are always very helpful.

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