coolant resevoir question

cichy1012 · Post by **cichy1012** » 25 Sep 2024, 09:32

2005 volvo s40 awd turbo, when the car is on the coolant is about 1/2 inch from the bottom. when its off it fills back up to between low and full. but its done a few wierd things.

i notice one time that it sat at the bottom still after about 15 mins after car was off, then i released the cap and the resevoir filled back up also. Is this normal. Thermostat problem? i replaced it about 4 years ago. Pain in the rear btw.

Post by **MoVolvos** » 25 Sep 2024, 14:27

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Check for combustion gas and if not a problem just keep an eye on the temp gauge. Thermostats usually causes temp fluctuations. Also, was air (pocket) somehow introduced into the system?
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The mouth of the Expansion Tank is quite large so use a funnel to seal with the tester on top. Be sure the spout of the funnel is not submerged in the coolant or it will be drawn into the tester.
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cichy1012 · Post by **cichy1012** » 26 Sep 2024, 08:23

the top of the resevoir had to hair line cracks in them for quite sometime. i replaced the resevoir but same thing happeing. i did not replace the cap, but have ordered one that should be here today or tomorrow.

Post by **MoVolvos** » 26 Sep 2024, 10:41

cichy1012 wrote: ↑26 Sep 2024, 08:23 the top of the resevoir had to hair line cracks in them for quite sometime. i replaced the resevoir but same thing happeing. i did not replace the cap, but have ordered one that should be here today or tomorrow.

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We had those cracks on our 08 C30 T5 and replaced both the Tank & Cap at the same time. Another problem area is the Octopus coolant hose where Volvo used glue for a split plastic coupler to squeeze the hose for clamping. The glue areas begin to crack and you won't see the leak as it's buried in the middle of the engine. The leaks are also very very small and progressive so the problem can go for sometime.

We cut the hose for ease of removal then examined the construction after the fact. Discovered could have just removed the pressure fit coupler and added 3 hose clamps as the hoses were still good. Arrow on glued seam.
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Upper Radiator Hose Auto Transmission - P1 S40 V50 C30 C70
Genuine Volvo 30723082 - 120334
https://www.ipdusa.com/products/9011/Up ... -gallery-3
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