Swollen upper radiator hose., Swollen upper radiator hose. Options

[valerit1]

I have a Celica 1995 GT. My upper radiator hose is OEM Toyota part, 7 years, 80,000 miles old. My radiator cap is new, OEM Toyota, correct 88Pa. NO overheating or drive-ability problems whatsoever.

When fully warmed, my upper hose is noticeably swollen, more so at the the engine connector. (which is to be expected as there hot coolant enters the hose before it bends).
I know OEM Toyota hoses last A LONG time. I replaced previous ones after 16 years, 150,000 miles as the precaution - they looked fine. I also know they are somewhat thin and soft even when new and supposed to swell somewhat by design.

I pressure tested my cooling system - perfectly fine. I got and tested several caps - new and used, and pressure tested them according to the OEM repair manual. Strangely, several OEM Toyota
caps I got - new and correct, 88Pa (.9 bar) actually open all past 1.5bar when tested! - some way more! (I tested about 5 from different souses - all correct 88Pa). The manual says should be within 74-108Pa, discard if less - says nothing what if more - is it OK? All cause the same hose swelling.
Now - I have one worn cap, opens almost at no pressure. That one of course causes NO swelling at all. And the car runs fine with it, no overheating whatsoever - just fills and overfills the bottle after a run - to be expected with very little pressure. That is it. And no - I do not have head gasket problems (it would not matter anyway as the cap would release the gasses)

NOW MY QUESTION - HOW MUCH SWELLING of the upper radiator hose is normal, by design, to ignore and nothing to worry about? General answers online have a lot of nonsense - you have this, you have that.

From your experience - what is the normal, acceptable swelling of the upper OEM Toyota hose car fully warmed up? With a brand new (or unworn) cap?

Thanks a lot!

Larry

[valerit1]

Here is a problem which baffles me. This happened recently when I replaced an old worn OEM Toyota cap (had about 3psi) - which I drove with for several years without any problems. Obviously with that cap there was NO swelling whatsoever. So the hose had been "underloaded" for years, so to speak. The old OEM cap has "ND" on the left wing and 0.9 on the right which stands for 0.9 bar= = 13psi = 88Pa, which is on the label. I cannot find this kind of cap any more. The new OEM Toyota style - "D" on both wings, same label 88Pa. Ok. I have collected 5 of them - new and slightly used, from different sources and places - and tested according to the OEM manual. (Attached) ALL of the new style open past 20Psi! - Some way past. Toyota OEM manual says reference range 10.7-14.9, replace if less - but what if much more? (See attachment!)
Once again - I tested 5!1 - all labeled 88Pa but test more like newer 108Pa standard.
May be Toyota decided to use the same spring for all and build newer vehicles both for 88Pa and 108Pa able to withstand the same? But my car is 23 years old Where can I find a cap which is build with more precision like Japanese used to be?
My point - I am sure if I could find a cap opening at 13psi or close around - as the manual reference range - I would have NO swelling! Makes sense?

I tried to find this precisely worn cap but could not - either very worn or very tight.
Where can I find a cap opening within the reference range? 20+psi is 50+%! More than the ratings! It is a lot! And I simply proved it - I got to another celica, attached pressure tester to the radiator, pumper to 20psi - woila - swollen upper hose looking just like mine!
Seriously - does it make sense? I tested over and over again SEVERAL caps - same result!
Please let me know what I am missing here. Thanks a lot!

[slavie]

Seriously - does it make sense? I tested over and over again SEVERAL caps - same result!
Please let me know what I am missing here. Thanks a lot!

The joke is, the definition of insanity is doing the same thing over and over again expecting a different result. If you tested 5, and all are the same, have you considered the possibility that the gauge you tested them with is wrong, and not the caps?

Your hoses are toast. Replace them before they blow, you overheat the engine and blow the head gasket on an engine design that is almost guaranteed to blow HG when overheated.

This post has been edited by slavie: Feb 23, 2018 - 10:13 PM