Radiator hose collapses when cold

My radiator hose shrinks quite a bit when the truck cools off.

I noticed it after when I filled my coolant the first time.

I just filled my coolant again and I’m noticing it happening.

When I open my radiator cap the radiator is full. The overflow tank is a little bit below the full line.

I read one symptom could be a bad radiator cap.

I actually think I have an aftermarket radiator.

I did order a new Toyota cap just now. Will it fit an aftermarket radiator?

Any other causes of the hose shrinking? Is the hose shrinkage normal? Is it something I should be worried about?

P.S. don’t ask why I wrote the replacement day and month of my radiator hose and didn’t include the year. Also the thermostat is new now so yeah... general record keeping on hoses... brilliant.

edit: just realized it says ‘19. I meant 2019. Ok past self, you aren’t quite so dumb.

 

Yep it looks aftermarket to me. That radiator cap is not OEM so I suppose the radiator isn’t either. Not sure what is causing this issue but I would have a mechanic look at it or try to replace the hose and make sure all your valves are tightened properly. I don’t think the previous owner would have just gotten a new cap so it believe it’s a new radiator and the cap that came with it. Best of luck.

Edit: I found this on boston.com

s the pressure in the system drops — when the engine is off and cooling down — the pressure cap allows the excess coolant in the overflow tank to return to the radiator. If the radiator cap is malfunctioning, the vacuum created in the system will collapse the hose

So it probably is your cap then. I suggest you changer the cap like what you have done (ordered) then do the steps that I suggested if the problem keeps occurring. Hope this helps

 

Either your radiator cap is bad or the hose going to the overflow bottle is plugged, make sure you check that hose and the port in the bottle for restrictions.

 

Thanks, I’ll blow out that hose as well.

Is it ok to use an OEM cap with an aftermarket radiator?

 

I don't see why not, should use the same cap.

 

@pontoon i believe so but I would do some research to make sure. Many aftermarket caps could be cheap and I’m not saying your is it’s just that some could be cheaply make and let pressure out easier than other ones. So if your getting an official OEM part from Toyota my best bet is that you’ll be fine but make sure to tighten your valves and make sure your coolant isn’t leaking.

Once you get it and put it on start your truck and go to the hood and check to hear if there is pressure coming out of the cap. Yes of course your engine isn’t hot enough to produce pressure but maybe wait a couple minutes and let it run. Be careful tho don’t get too close just in case.

 

I was taught at the very beginning of my apprenticeship that this is symtoms of a failed cap.

I'd suggest OEM or Standt https://www.rockauto.com/en/moreinfo.php?pk=48500&cc=1364723&jsn=840

 

Is it damaging to drive it like this? Coolant level seems good. The only thing I notice wrong is the hose collapses.

 

Your probably ok but there is the risk of over-pressurizing the cooling system if the cap isn't venting properly.

 

I'd drive it nearby to get a new cap but not much more..not worth risking blowing the hose

 

Dm93 has it diagnosed.

 

It seems like the radiator cap fixed the issue. Thanks all

 

Follow up… I eventually learned the cap did not fix the issue. The problem is I had an aftermarket plastic cheap radiator and the manufacturer forgot to drill out the overflow tube. So the overflow tube was blocked by plastic. I just drilled it out the way it should have been from the factory and it works great now.