Recently I changed out my radiator cap due to a rust hole forming on the old cap. Since replacing my old cap, I now find that I am losing water and the temp goes up when stationary, such as at lights. Prior to changing caps I had no issues. The cap is the correct pressure or at least stamped with the correct pressure, 15psi. I do not have an overflow tank. Is it possible that the new cap is faulty and can it be checked. I do not mind buying another cap, if that's the issue. Has anyone else had this same issue.
11 replies to this topic
#2
MFM
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Posted 24 May 2019 - 12:50 PM
Wondering whether the old cap was not holding any pressure so was allowing heat to release, or something has rusted off the inside of the old cap (as it sounded stuffed) and dropped into the radiator and is blocking something? Was he rubber washer still attached to the old cap?
#3
Dr Terry
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Posted 24 May 2019 - 01:05 PM
I think you now have a leak at a hose or water pump or similar, which wasn't noticed previously because your old cap didn't hold any pressure. With the new cap the system will go to 10-15 lb at normal temp.
The overheating situation will then be the result of coolant loss.
If we assume that the new cap is OK & is also sealing properly at the radiator neck, get the system pressure tested.
Also you could get a torch & have a look at the bottom of the water pump & any hose joints for any evidence of coolant.
Dr Terry
#4
arrimar
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Posted 24 May 2019 - 04:50 PM
...and perhaps check inside the cabin for heater core leaks.
#5
_1ARC_
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Posted 24 May 2019 - 05:10 PM
The old cap was intact except for a pin hole on the cap that I caused when scaping at the rust. The coolant is clean and the tubes, that I can see, are clear of debris. There is no sign of coolant leaking as I am using a green coloured coolant which should be seen. I will have the system checked out including the heater core. Thank you for your valuable feedback.
#6
RallyRed
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Posted 24 May 2019 - 05:31 PM
Hi..normally the smell of the coolant leaking will get your attention. Any smell mate?
#7
torana74
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Posted 25 May 2019 - 12:20 AM
I don't think the pin hole in the old cap would've in any way have been detrimental to your coolant system as it the seal seating on the neck that does the job. Does the new cap seat correctly? When putting the new cap on is there tension to push down and turn to lock? Is the seal on the new cap the same distance from the lid as the old one? Squeezing the hoses when it's at operating temp, is there pressure in the system? If it's releasing pressure it will have the symptoms described
#8
_1ARC_
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Posted 25 May 2019 - 10:44 AM
There is no smell or visual leaking of coolant. I am going to buy another cap today and take the car out for a run. The tension of pressing down before twisting the cap on is not as much as the old cap. For peace of mind, I am having the system tested. Cheers
#9
LHSL
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Posted 25 May 2019 - 01:59 PM
Maybe a dumb response but did you get the correct non reservoir cap? Could whilst getting warm open to transfer to reservoir but nothing there so coolant lost thus a low level and the car gets warmer each time.
Edited by LHSL, 25 May 2019 - 02:00 PM.
#10
_1ARC_
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Posted 25 May 2019 - 06:52 PM
The cap is a non reservoir type. The cap is CPC 15 pound cap where I was told the reservoir type is 13 pound cap. I brought another today and I will compare the two. If I continue to have issues I will have system checked out. It is strange that I had no issues until I changed out caps. I will update topic once I find what has or is happening.
#11
_1ARC_
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Posted 27 May 2019 - 12:14 PM
Just an update. I purchased another cap and compared the two. I measured both caps from the copper base (that sits on the top edge of the filler neck) to the top edge of the rubber ring (that sits at the bottom of the filler neck). I found that the cap I was having an issue with is 1.1mm shorter that the other. I fitted the latest cap and all back to normal with no water loss and no temp rise. So, my presumption is that 1.1mm was enough to not seal enough to hold pressure below 15pounds. Both caps are CPC and I am thinking of writing to them to advise of the mismatch.
#12
RallyRed
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Posted 27 May 2019 - 12:54 PM
nice work
Also tagged with one or more of these keywords: Cooling System
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Water Pump LeakingStarted by _1ARC_ , 12 May 2018  Cooling System
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