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Post by jonty1951 on Nov 20, 2011 16:25:24 GMT
During a drive out this morning, I noticed that my water temp gauge went up to the halfway mark and then back to just below, which is where it is normally This has never happened before as far as I know. Oil and water levels seem OK. The head gasket was replaced 5 years ago, so I cant think it was an airlock after all that time! Should I be concerned, or is this something that does happen?
John
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Post by Jerry & Di on Nov 20, 2011 17:38:06 GMT
Never happened on mine. Worth checking that you have no air trapped in the system at all three points. I find it easier with the rear of the car higher up. The jiggle valves are supposed to get rid of any entrained air as and when/if it appears. Might be worth checking your jiggle valves to see if they are still free
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Post by jonty1951 on Nov 20, 2011 18:04:35 GMT
Thanks for that Jerry, so how/where do I check the bleed points? How/where do I check the jiggle valves?
Thanks John
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Post by petevick on Nov 20, 2011 18:57:15 GMT
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Post by helsbyman on Nov 20, 2011 19:57:19 GMT
how long was it standing as it may have just been a sticky thermostat
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Post by Jerry & Di on Nov 20, 2011 21:29:39 GMT
How/where do I check the jiggle valves? Thanks John One of them is in the alloy which the narrow bore rubber pipe goes to from the header tank to the inlet manifold/cylinder head. Clamp the pipe off and poke down the metal stub with something like a welding rod to see if you can get coolant out and feel the ball bearing moving. The other one is in the engine compartment, again attached to the other thin rubber pipe from the coolant header. The plastic fitting will come apart and you can ensure the s/s ball can rattle about in the plastic housing.
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Post by jonty1951 on Nov 21, 2011 5:42:40 GMT
Many thanks guys for the excellent info ! Just out of curiosity, I carefully removed the radiator bleed plug (engine was cold), and could hear a slight hissing of escaping air. The radiator core was also visible, until the coolant rose up to the top of the opening and then settled. I wonder if it was bled fully when the HG was replaced ? I've also always noticed that the heater goes cold on tickover, but then goes hot once the engine speed rises. Is there a clue there perhaps ? In reply to Helsby, I was driving at about 50 mph when I noticed the temp gauge fluctuation, not stationary ( is this what you meant?). I'll keep an eye on it today, and see what happens!
John
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Post by petevick on Nov 21, 2011 6:53:48 GMT
.....Just out of curiosity, I carefully removed the radiator bleed plug (engine was cold), and could hear a slight hissing of escaping air. The radiator core was also visible, until the coolant rose up to the top of the opening and then settled. I wonder if it was bled fully when the HG was replaced ?...... thats the biggest clue to an air lock as I've ever seen !! You need to do the other two points as well. Did you check the expansion bottle level after bleeding the rad ??
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g4wam
Junior Member
Posts: 45
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Post by g4wam on Nov 21, 2011 13:58:21 GMT
hello -take a look at the expansion tank cap while your at it, or better still just replace it. I have opted for the continual bleed routine , fit a mike satur bleed nipple to the radiator top and bleed the coolant regularly whilst checking the bottle level of course.
Mike
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Post by SWMG Admin on Nov 21, 2011 15:51:19 GMT
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Post by jonty1951 on Nov 22, 2011 5:43:04 GMT
I opened the bleed nipple on the heater , but there was no sign of any air present. The water level in the main radiator was still OK. The Temp gauge worked as normal yesterday, so perhaps the low level in the radiator did have something to do with it. With regards to the heater blowing cold when idling, I'm sure I read somewhere this can happen due to the long run of the coolant pipes (or something like that !) Does anyone else's heater behave like this ? (I'll try and get round to bleeding the rest of the system this weekend).
John
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Post by petevick on Nov 22, 2011 7:08:20 GMT
.....With regards to the heater blowing cold when idling, I'm sure I read somewhere this can happen due to the long run of the coolant pipes (or something like that !) Does anyone else's heater behave like this ?....... never happened to me in 8 years of ownership, old wifes tale When you bleed again, you need to do all 3 points as any air left in will be moved around, possibly back to the rad again
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Post by Jerry & Di on Nov 22, 2011 8:45:36 GMT
Wot he says above I re-plumbed my coolant pipework when I fitted the TF160 intercooler so the heater pipes are piped in with swept "Y" pieces for both flow and return in the enlarged by-pass circuit. I have the thermostat under the washer bottle, so the by-pass circuit is large, always moving, and the heater is directly connected to this stream. It is also easier to bleed with this arrangement as everything is larger bore with no restrictions. Sometims, in the winter, the thermostat never opens - sufficient cooling in the under floor metal pipes. I can tell 'cos I have an additional temperature gauge, in place of the clock, which senses the temperature in the metal pipe near the bleed point over the gearbox. Wish I could draw it out, but not that clever
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Post by petevick on Nov 22, 2011 9:19:28 GMT
.....Wish I could draw it out, but not that clever you need to do it as an ISO pipe drawing, similar to this.......... you can buy the ISO graph paper. 9 is a reducer, 6 is a valve etc. used to do these when I worked for a sugar processing equipment manufactures, really enjoyed doing them.
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Post by jonty1951 on Nov 23, 2011 18:17:17 GMT
Seemed to have disturbed something ! I took off the rubber pipe connected to the jiggle valve enclosed in the alloy housing on the engine. I'm pretty sure there was a bit of resistance when I blew down it, but then it went clear. I ran the engine up to temperature, which caused the expansion tank to gush ( I was running it with the pressure cap off, is this normal ?) The heater is VERY HOT, but still goes aired on tickover, and the coolant has now gone a mucky, brown colour whereas before it was more of a blue colour. I also checked all the bleed points, albeit on the level, and there was not much sign of air. I realise it probably requires all flushing out and new anti freeze adding, but it's not really time of the year for crawling around under a car ! John
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