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Cooling System Questions

Posted: Sun Aug 30, 2015 3:49 am
by sticky nicky
Wondering if anybody can answer some questions for me?

Today I replaced my coolant after getting a burst pipe at the track. The pipe I replaced was the small one coming from the inlet manifold to the ISC valve. I then emptied and filled the system which I have done numerous times before without issue. On bleeding the system and running the engine the thermostat seemed to open but there didnt seem to be alot of flow through the top radiator pipe, which steadily got hotter, into the top of the radiator. I had the radiator cap off and was watching the coolant, it did seem to be flowing a bit as I could see the coolant swirling.Should it be a faster flow? I kept it running and eventually the fan came on but wasnt going off and on feeling the lower hose it didnt seem very hot at all and the lower part of the radiator was also very cool. The temp gauge was just under the middle mark.

To try and cut a long story as short as I can. I suspected an air lock or faulty water pump and thinking that the only difference from today and previous times was replacing that pipe. I thought I would check the coolant flow from the inlet manifold outlet forwards in the direction of flow as per the diagram. I removed the end of the pipe that went into the ISC valve and nothing came out of it when taken off. There should be some coolant in the pipe I am guessing. I turned over the engine with the pipe still off and coolant flowed out. So the water pump is working. Put the pipe back on and then removed the pipe that goes from the outlet of the ISC valve and into the air valve. Again nothing came out so turned over engine again and coolant flowed out. Put the pipe back on then removed the pipe marked number 1 in the pic to make sure that coolant was flowing through the air valve and out of the outlet pipe on the valve. On turning over the engine this time instead of getting the flow through the air valve outlet pipe as I expected it pumped out of the hose I had removed. This shocked me as considering the direction of flow in the diagram, and the actual flow to that point, it was actually coming out in the wrong direction. Surely this is not right. Can someone confirm this for me? Surely it should be coming out of the air valve outlet not out of the return pipe that goes down to the T piece on the thermostat housing.

I also noticed going by the pic that pipes 2 & 3 are on the wrong way round on the air valve on my car. It has been like this for ages and havent had any noticeable problems so I guess the flow direction through the air valve doesn't matter?

Any help is appreciated :D


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Re: Cooling System Questions

Posted: Sun Aug 30, 2015 12:21 pm
by sticky nicky
Just to add that when the thermostat is open, or appears to be, that pipe no.4 is hot and pipe no.1 is cold. Shouldnt pipe no.1 also be hot once the coolant is circulating ?

Re: Cooling System Questions

Posted: Mon Aug 31, 2015 8:24 am
by Rovy
Pipes 2 & 3 are on the wrong way round on the air valve also on my NA. It looks OK otherwise they would cross over.