adarm

Overheating

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Hey guys, I have a 2001 bug, running 345 bhp, forged engine etc...got a mitsomoto rad...about 25 mins into driving, I get a massive engine spike in coolant temp, see below pic...I took it to another garage to change stat, and still does the same...the engine feels cool... the coolant level doesn't drop, the pipes have been checked for leakage etc and all seems to be fine...it didn't do it before before rad was changed. The guy who has done the work things it maybe the temp sensor, any ideas and thanks in advance??d0d836f4c65e13f593b47560ef7c479e.jpg

 

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The first part of the graph looks normal upto 92 and back down to 80 when fans kick in. Thats how my hawkeye reacts. But the spike is not normal obviously. If the car does not overheat or push coolant out of overflow then it is likely the sensor or electrical. More info, was car just ticking over or while driving, as above coolant, hoses feel firm but not solid when hot, does the fan kick in, does the heater blow hot air, etc?

Have you got the rad cap and filler tank cap on the right way round (been know to get swapped)? The winged cap goes on the filler tank (next to intercooler) and the non-winged cap goes on the rad.  I assume a Bug is the same. Rad cap is just a release cap and the filler is a two way cap, when car cools the vacuum created sucks water back in through the filler tank cap. They must be on the right way round. Also if rad just changed do you have air lock in the coolant, can be ****** things to bleed all the air out. If not filled correctly this is easily done. Just a thought

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Thanks for the response dude...first time it happened took it for a burn, and then literally driving down my road, put car in neutral and started going into 109..then got stat changed..then today took it for a burn, stopped at shop, kept engine running, whilst driving home shot upto 115...fans do kick in... when I turned it off then on again, without starting the car, the fans run for like 10 mins...hot air is coming out of fans :) caps are all on fine, while double check in the morning.. when temp is going high and I stop car, coolant is very high in overflow tank, when it's cold and I check 1 hour later, rad sucks more fluid in and not as much in overflow tank.
Thanks again bud :)

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Seeing as it didn't do it before the new rad was fitted , I'd suggest checking for a airlock . Personally I've never had any issues with refilling the coolant system and getting a airlock afterwards but I've seen a lot of posts about airlock problems and one was from a main dealer getting a coolant airlock .

 

When up to temp (fans cut in ) Does the heater blow hot air and are all the coolant pipes getting hot once the thermostat has opened?

Ie top bottom hoses and heater matrix flow and return (at the bulkhead )

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Once air is trapped it is a bugger to get out if an airlock (hopefully). Best bet is to drain it out and start again. I refill from the big hose that goes into the filler tank, at back goes to turbo. This fills from the bottom up. Leave rad cap on and fill up (slowly) until filler tank is 3/4 full and then bleed as per repair manual (many videos on youtube). I even had a Subaru main dealer fill and try to bleed from the radiator doh (dashcam). So even so called pros do not know what they are doing. The cooling system on a subaru is rather convoluted.

Is coolant being pushed out of the overflow tank after a hard run? It should raise and fall with the heat cycle. My hawkeye overflow tank when engine is cold at full mark when engine hot inch from the top (not brimming but quite high). Do you have dried coolant marks around the overflow tank as if coolant has spurted out of the tank?

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Hey dude, after hardish run, coolant is high ( in overflow), when it's cold, it sucks it back in to the rad... I watched a few video of how to bleed it out...so far it seems to have worked (see pic below)...car is back in garage getting some spray work done, but seems to be working fine... when opened the top, as seen in picture, before I put funnel in, I could see lots of air bubbles, then put funnel in, it rose u into the funnel, lots of little air bubbles coming out, I run it for 15mins (heating was flat out and very hot)...then turned it off, let coolant drain back into car, then screwed cap back on :) get the car back thursday, so will give it some shizzle and see what happens... I cannot thank u enough for all your advice... top man!!13a8b275c1c8c8ac8f8e4de000168394.jpg

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Checked hoses, all hot and top hose still squishy :)

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Hey mate...I changed the header tank to mitsomoto as a few people said that if dif pressure on rad cap and header tank cap it will dump all coolant into overflow...I have now changed the header tank and it's doing that same...do u think it could be a blocked rad, even though its new?? Thank buddy :(

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The heater matrix could be blocked bud, when i flushed mine i also took the two hoses that go through bulkhead off and ran the garden hose through it some amount of s**t came out, could be worth a try 👍 

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I would do as Stuartie said and start again and refill very slowly via the turbo hose. This fills it from bottom up. Once air is trapped in the system it is very difficult to get out. Only real way is to start again. PIA but if you keep overheating it that will become expensive. Make sure the car is flat or point up hill when you fill it.

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Update....my new mitsomoto rad has a block on it at the top, partial block, ffs, at least I know now...thanks so much for everyone's help dudes :) will keep you updated when I get a new one #paininmyarse

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First pic, the Alan key will not go any further, 2nd and third u can see it goes all the way in ( that's what she said )4c99041dc18cc6fb57b5c0cc7b27ec22.jpgd10355e4e7011d84f580f61945a85869.jpg58e146a899b5a33fc7b405acb3c31bcd.jpg

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For those who are interested...mother !Removed! mitsomoto...utter ****!!!edeeba4aba0b3336bfec4f7b5623dd41.jpg

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I have heard other people state they would not put mitsomoto stuff on their car, now I see why. Luckily I only have the rad hoses. Glad you found the issue.

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i got flack for saying mishicrapo stuff last week haha

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9 hours ago, adarm said:

Show them my pic will shut them up 🙂

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haha yeah 😄

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