98 S70 upper radiator hose again

mar601 · Post by **mar601** » 26 Apr 2024, 13:26

Thanks so much for all the help here. My upper hose popped off again (new hose, oem clamps) Going over right now to get OEM cap and get rid of that URO.

Question though --
When the car is running, should I feel a "fullness" in the hose from coolant? Because I don't. (!?)
I can press in on the hose and it has the feel of nothing but air in there. I can press one side of the hose till it touches the other side.
Should i feel "full" ?

Yet -- the car has never run as good as it does now. It's like it's in a "sweet spot" after my 23 years of ownership. Also, the temp gauge can go a little above midline but that's it.

Also, would anyone know the part number of that small hose that connects from the tank overflow back to main hose?
Does it get clogged? -- thanks

Post by **scot850** » 26 Apr 2024, 16:26

There are 2 shown for a 98 turbo engine. A long one which is for the one from the top RH of the radiator and the shorter one is from the top of the thermostat cover to the coolant header tank.

Longer one: Pt# 9470676

Shorter one: Pt# 9135267

https://www.volvocarstorontoparts.ca/a/ ... 66722.html

I don't recall you responding on the questions I asked about the radiator and hose.

How old is the upper hose?

What brand?

Is the metal sleeve tight in the upper hose if it is an OE radiator?

Neil.

mar601 · Post by **mar601** » 26 Apr 2024, 17:19

I have the shorter one -- thanks. I replaced the upper radiator hose the other day and the radiator, now that I recall was replaced maybe 20 years ago. Used this hose with the oem clamps.... https://www.amazon.com/dp/B000C0YP6I?ps ... ct_details Just as durable it seems as the original which was in bad shape. Like I say though, should I be able to squeeze it when the car is running? It's like there is nothing but air in there. Shouldn't it be full of fluid? (Not a mechanic). I don't see a metal sleeve? on the radiator. I just have a "port" on the radiator where the hose attaches. No issues for years till now and the hose keeps popping off. Even the new hose did it today.

Post by **abscate** » 27 Apr 2024, 04:35

It should be full of fluid but it is squeezable when the car is idling or not too hot. After a long hard run it should be hard to squeeze with two fingers

mar601 · Post by **mar601** » 27 Apr 2024, 07:42

Ok thanks. Also -- when I remove the expansion tank cap (slowly) and the car is hot, my coolant is boiling and bubbling. I'm guessing it shouldn't do that? Could I possibly need a new thermostat? Going to try and look closer today so may be beack with more questions. Thanks very much. I've been going through so much coolant, I've been getting this stuff....(probably a no no)
https://www.oreillyauto.com/detail/c/o- ... lant&pos=0

And like I say, the car has never run smoother or better since I've owned it. Even with this going on, wouldn't a head gasket issue create a rough running engine? not? (I did order one of those combustion gas test kits that was recommended).

Post by **scot850** » 27 Apr 2024, 08:34

Never open the cap with the engine running if the car is up to temperature. It will suddenly depressurize the system and could spray boiling coolant over you.

Thermostat could well be an issue. However, your engine would overheat if it was stuck shut and it would take a long time for the upper hose to heat up. It you have not replaced the thermostat in the last say 4-5 years it is past due. The foreman at my local dealership I knew well recommended changing it every 3-4 years along with the coolant flush. Maybe a little overkill but cheaper than a head gasket.

It does sound like you could have an air lock in the system. But unless you recently changed the coolant it would be strange for that to happen and unlikely. The only way for that then to happen is a head gasket failure.

As I believe was suggested before, there are kits to test for exhaust fumes in coolant.

Neil.

mar601 · Post by **mar601** » 27 Apr 2024, 09:01

Yes Neil. I just edited my post to say I ordered that gas test kit. Yeah, when the hose blew off (again) yesterday that's when I took off the cap come to think of it and it was boiling. Ok -- stuck at home so no choice but to try and figure it out. I also have an infrared thermometer coming fro m amazon today. Is there a threshold reading that the engine temp should not exceed? Just point it at the engine block?
Thanks very much.

And..can you tell me which thermostat to get? I remember I replaced one years ago and there were "choices" ?
98 S70 T5 with 2.3L
OEM Volvo 271664/71 ?
I see different temp ratings on them 160, 180, 192? And there has to be a gasket included right?

Post by **volvolugnut** » 27 Apr 2024, 09:03

Top of the radiator is traditional test of coolant temperature.

volvolugnut

Post by **scot850** » 27 Apr 2024, 10:59

Most replacement thermostats should come with the rubber gasket. AS to which one to use, the reason there are options is based on the climate where you live. I would contact a dealer parts department and ask them which temperature rating one you should buy.

If you are buying aftermarket, make sure it has the small bypass valve in the thermostat. I have seen several aftermarket ones that don't and when they stick they will give you no warning. The bypass versions give you a little bit more protection.

Try looking at this thread and see if any of it helps you:

viewtopic.php?t=67980

Neil.

mar601 · Post by **mar601** » 27 Apr 2024, 12:08

I just got my thermometer and ran the car. Fact is, when I press on the upper radiator hose it gets to the point where it feels like it's going to burst even before the thermostat supposedly opens. Like it's being filled with air -- so I shut it off. Car runs great -- no rough idle or anything but I'm guessing that is combustion gas building up? (Hope not of course). I have that kit on the way. If it is combustion gas, is it more liable to blow off the upper hose?

I think it may be getting worse because I could actually press in on the hose the other day when it was running. It looks a bit like an innertube that is overinflated now.