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Over heating Issues continue, the fun continues... Please help


ripped_fear
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Hello all I'm going to keep this as brief as possible but explain everything I can so here goes bare with me...

 

First the car in question is a NA 5 speed.

 

During Dragon ball the car suffered with over heating when going over 60-65mph causing increased pressure in the rad hoses and vacuming of the top rad hose when it cooled down. This also caused the water to be pumped into the expansion tank causing it to fill to the brim along with it pumping air into the tank too. I had to keep speeds low and heater on to keep temperature at half.

 

While I was on DB I got a new rad cap from another member and after 30mins driving it soon became apparent this had not solved my issue.

 

So on return I had the water tested fro HC's and it came up zero so this would suggested the head gasket is fine(this has now been done a few times to be sure), so we removed the thermostat to see if the problem stopped but everything continued.

 

After talking with the garage my viscous fan was not working at full efficiency + having spoke to keron he suggested it could be water pump issues. So it had a new OEM water pump, new OEM thermostat and second hand, but fully functioning viscous fan/clutch. Still no improvement.

 

So next we check the heater matrix by removing the top hoses at the back of the bulk head and pored water into them and it flowed nicely so this has me thinking this is not the issue.

 

We also flushed the system through many times to remove blockages and all seemed fine.

 

Next we tried to bleed the systeme again by jacking the front up as high as possible this seemed to work and lots of air came out then all of a sudden the car coughed, and idle started to bounce by about 200rpm and when taking up the road it was missing.

 

Took the car back asap and left still for about 30mins and fired it up to move into my drive for the night and the miss had gone and idle was now fine.

 

The next day I put another brand new OEM rad cap on, and result!! when driving, even heavily the cars temperature stayed bang on! No expansion tank issues, vacuming etc all good, temp nice and steady.

 

Now this is where the fun begins...

 

I took the car away on Sunday and all was well, until I pulled onto the Motorway, ten mins in at 70mph the temp started to rise, pulled off to check the expansion tank and all was fine under there, but car was still getting hot. I drove the car the whole trip and as long as its under 60mph the car seems fine, temp good, expansion tanks good etc but as soon as i get near 80mph or go up a long steep hill the temp goes up.

 

Im now stumped as to what it can be, as the problem is now allot better as the expansion tank is fine, the coolant levels are staying nice, no vacuming, but the temp only goes up and high speed or when the engine is under load,

 

The only thing i can think of is to get a new rad, an other ideas at all guys?

 

I'm getting a bit sick of this now.

Edited by ripped_fear (see edit history)
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well if there is nothing else to change then the rad is next on the hit list i would say what condition is it in?

 

Im thinking this too. It does look in good nick though, few bent fins but good.

 

I mean compression tests....us Geordies are proppuurrr fick.....dadduuuurrrr!

 

No it hasnt but it has had the emission rod thing to check for hydro carbons. I wouldnt even no how to go about a compression test, is it a simple thing?

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compression test is easy get a tool from halfrauds and remove spark plugs and put the tool in its place take the main fuse out for injectors the wide open throttle while turning it over the read what the tool says,then repeat on the next cylinder

 

have you tried a propper rad frush just might be gunked up

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You would expect the temp to rise under load and speed drivingm thats normal tbh. Have you got a calibrated temp gauge to see how much the temp is going up? Could try a rad flush first, seeing as you've changed just about every other component in the cooling system.

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compression test is easy get a tool from halfrauds and remove spark plugs and put the tool in its place take the main fuse out for injectors the wide open throttle while turning it over the read what the tool says,then repeat on the next cylinder

 

have you tried a propper rad frush just might be gunked up

 

You would expect the temp to rise under load and speed drivingm thats normal tbh. Have you got a calibrated temp gauge to see how much the temp is going up? Could try a rad flush first, seeing as you've changed just about every other component in the cooling system.

 

Rad has been flushed by my self and once it had been down I had the hose through it and it ran lovely.

 

Compression test seems the way forward but the problem is on the NA thats an inlet off job by the sounds of things. May book it at toyota for that one.

 

You say you expect the temp to rise but it never did before, it always stayed on half weather I was going 10 or 110.

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i had a very similar problem with my MR2 5 years ago when i bought her.....left her with Rogue Motorsports ( MR2 Specialists )..they did all the gas tests and compression tests and they showed no problems....BUT my car would only overheat when driven hard on boost - normal steady driving she would be perfect, but turn the power up a bit and the temp gauge would rise very quickly..Rogue phoned me and asked me if i wanted them to take the head off and check the gasket visually as all other tests didn't show any problems...this they did and turned out to be a hairline crack in the head gasket just between a cylinder and a waterway thus allowing the coolant to immediately overheat..

Just my thoughts seeing as you have tried almost everything else...hope you get it sorted soon though matey..nothing more annoying

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you not prepared to do the head gasket?...seems a bit drastiic to break her because the hg has gone ( imo of course )...she looks a nice car..

 

she is a very nice car and apart from this has been faultless. Love it to bits but to do a HG its going to cost around 1k all of which will be dead money as im looking to get a TT soon. I could break it and get similar money I reckon.

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she is a very nice car and apart from this has been faultless. Love it to bits but to do a HG its going to cost around 1k all of which will be dead money as im looking to get a TT soon. I could break it and get similar money I reckon.

 

Head gasket may be £1k+ to do, but getting someone like Keron to do an N/A-N/A swap will be a lot less, I'm planning on getting an eco freindly diesel soon aswell so I could always give you a lift from Keron's back to the port and back again for minimal diesel costs if needs be :)

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