98 S70 upper radiator hose

mar601 · Post by **mar601** » 20 Apr 2024, 08:36

My upper radiator hose has come off twice and I swear I've tightened it to the point where no way it shouldn't do that. Can the coolant system build up so much pressure that it can blow off? Bought a new hose and will clean everything -- maybe some light oil or something causing the connection to loosen? It's the end on the radiator itself. -- thanks

I was going through a car wash yesterday and it came off. Very stressful.

Post by **volvolugnut** » 20 Apr 2024, 09:10

Yes, over pressure of the coolant system can blow off hoses. The cap on the coolant overflow tank is the over pressure relief. They can fail.
You may also have a head gasket problem allowing exhaust gas pressure in to the coolant system.
You could modify an old coolant cap to add a gauge for the coolant system, or use a commercially available coolant system pressure gauge.
There are also commercial test kits for exhaust gas in the coolant.
volvolugnut

Post by **MoVolvos** » 20 Apr 2024, 09:19

.
Was helping a neighbor with his Capital Auto Auction

2003 Camry. He brought over with him a kit from Amazon. I think it's this one but not sure? I told him it showed no signs of high pressure or coolant leak so didn't open the card board box it was in.
.
BT-500 Head Gasket Combustion Leak Test Kit - Made in USA
(www.amazon.com/Block-Tester-BT-500-Comb ... C93&sr=8-2)
.

.

mar601 · Post by **mar601** » 20 Apr 2024, 12:20

Many thanks.

mar601 · Post by **mar601** » 20 Apr 2024, 12:29

This is the one on the car now. Just bought it. How does the cap relieve pressure? Seems it just screws on very tightly and seals the opening. ? thanks

https://www.amazon.com/gp/product/B00BQ ... 0DER&psc=1

Post by **volvolugnut** » 20 Apr 2024, 17:19

mar601 wrote: ↑20 Apr 2024, 12:29 This is the one on the car now. Just bought it. How does the cap relieve pressure? Seems it just screws on very tightly and seals the opening. ? thanks

https://www.amazon.com/gp/product/B00BQ ... 0DER&psc=1

The cap has a spring relief built in. It will raise and vent at a preset pressure. The cap you purchased does not have pressure setting listed on amazon. URO brand does not have a good reputation here on MVS.
volvolugnut

Post by **scot850** » 20 Apr 2024, 17:24

Is the radiator on your car recent or the hose? What brands did you use?

Neil.

mar601 · Post by **mar601** » 21 Apr 2024, 07:37

The radiator and hose are original volvo from 1998 -- bought this hose...
https://www.amazon.com/dp/B000C0YP6I?ps ... ct_details

Ok, so I'll send the cap back and go to volvo to get the original part. The original sure looks the same...
https://www.ipdusa.com/products/9421/Co ... vo-9445462 ?
thanks.

Post by **jreed** » 21 Apr 2024, 07:40

I took apart one of those aftermarket Gates expansion tank caps a while back to see all the springs, disks, gaskets, spacers and other pieces inside. It was more complicated than I had been expecting:
viewtopic.php?t=102293

Post by **scot850** » 21 Apr 2024, 08:25

Unfortunately Amazon has started using a stupid across border link suppressor so I can't see what those in the US post and similarly for you if I do.

Going back to the original parts. If your radiator is the original then congrats on it having lasted this long! One thing to watch for which killed my original radiator was the top hose has a brass sleeve insert. On mine this started to slide out of the upper pipe which in turn meant the top pipe was squishy and not firm. This is turn meant the pipe would not hold shape and leaked. It also protects the strength of the plastic. Mine sheared off where the sleeve moved from.

With the hose the old hose goes wither squishy or hard and won't allow it to tighten and it will leak. Replace it.

Neil.