Swollen radiator hose

VALERIT1

MEMBER
1995 TOYOTA CELICA
2.2L
4 CYL
2WD
AUTOMATIC
230,000 MILES

I have the car listed above it is the GT model. My upper radiator hose is OEM Toyota part, seven 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 sixteen 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 it was perfectly fine. I got and tested several caps both new and used, and pressure tested them according to the OEM repair manual. Strangely, several OEM Toyota
caps I got were new and correct, 88Pa (.9 bar) actually open all past 1.5 bar when tested! Some way more! (I tested about five from different souses all correct 88Pa). The manual says should be within 74-108 Pa, discard if less it says nothing what if more, is it okay? 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 it just fills and overfills the bottle after a run which is 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

6 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good afternoon.

No swelling is normal. That is a sign of internal failure in the construction of the hose.
Replace the hose.

Roy

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Wednesday, February 21st, 2018 AT 12:57 PM

VALERIT1

MEMBER
3 POSTS

Well, may be swelling is is a bit of harsh word? Bicycle tube is also "swollen" when inflated. Could you please take a look at all the pictures cold and hot hose. Please disregard all white stuff on the hose. My attempt to wrap a tape over it. There is absolutely no damage or compromise visible or felt on touch, the hose look and feels as it was new. In fact if was swelling when new. I just do not remember how much since I drove several years without pressure (bad cap). By the way, the lower hose is also hot, hard and swollen but not as much. Thanks a lot! Appreciate your help!

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Wednesday, February 21st, 2018 AT 4:44 PM

KHLOW2008

MECHANIC
41,814 POSTS

Bicycle inner tubes are designed to be swollen when inflated, to keep the outer tube in its desired shape. The outer tube is not supposed to be swollen.
Radiator hoses are not designed to be swollen. Your radiator hose is fatigued and it is at one area. If it is normal, the whole hose would be similarly swollen.
One hose that last you fifteen years does not mean the next would too. Machine or anything related are like man, they do not all die at the same age, no matter how healthy they might seem be.
It is our duty to provide the our recommendations but the onus is on you to change or not.

Good luck.

K H Low

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Wednesday, February 21st, 2018 AT 10:36 PM

ASEMASTER6371

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52,797 POSTS

I agree. The hose itself is the issue. The internal support in the construction of the hose has failed.
You need to replace the hose.

Roy

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Thursday, February 22nd, 2018 AT 1:15 AM

VALERIT1

MEMBER
3 POSTS

Okay possibly. But, 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 "under loaded" 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. Okay. I have collected five 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 five! 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 twenty three 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 - voila, 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!

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