Hi,
I had a slight scare today.
I drove my car from home to the nut and bolt shop and noticed the temp had gone through the roof.
I stopped, checked if the head gasket had blown. No milk in the oil.
I think it's still blown.
I let it cool and drive to home, and then suddenly the temp goes back to normal (50% on gauge)
I imagine this is the thermostat staying closed and then suddenly opening, flooding the engine with cold water.
Correct?
Temperature rise and then suddenly goes back to normal?
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Re: Temperature rise and then suddenly goes back to normal?
An airlock in the system can cause the symptoms you describe it could also be a worn radiator cap leaking pressure or the thermostat not opening properly.
I'd start by fitting a new rad cap, top up the coolant to the brim of the radiator neck, then run the car on fast idle with the rad cap off, if the level drops keep topping up the coolant. Once all the air is out of the system fit the rad cap and then leave ticking over until it gets up to temperature keeping an eye on the temp gauge and checking for any leaks.
I'd start by fitting a new rad cap, top up the coolant to the brim of the radiator neck, then run the car on fast idle with the rad cap off, if the level drops keep topping up the coolant. Once all the air is out of the system fit the rad cap and then leave ticking over until it gets up to temperature keeping an eye on the temp gauge and checking for any leaks.
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Re: Temperature rise and then suddenly goes back to normal?
Could be a bad ground?
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Re: Temperature rise and then suddenly goes back to normal?
Nic wrote:An airlock in the system can cause the symptoms you describe it could also be a worn radiator cap leaking pressure or the thermostat not opening properly.
I'd start by fitting a new rad cap, top up the coolant to the brim of the radiator neck, then run the car on fast idle with the rad cap off, if the level drops keep topping up the coolant. Once all the air is out of the system fit the rad cap and then leave ticking over until it gets up to temperature keeping an eye on the temp gauge and checking for any leaks.
Thanks, I'lll do all that then!!
Get a thermostat anyway? only 8 quid.
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Re: Temperature rise and then suddenly goes back to normal?
synXero wrote:Could be a bad ground?
On the temp gauge/sensor?
When i opened the bonnet there was a lot of steam coming off the thermostat housing. It was definitely HOT!
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Re: Temperature rise and then suddenly goes back to normal?
went for another test drive and it did it again
Re: Temperature rise and then suddenly goes back to normal?
Don't drive it until you've sorted the problem, you could cause serious damage if it overheats.
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Re: Temperature rise and then suddenly goes back to normal?
I topped up the coolant, I thought I had. I did what matey above did.
I get a new thermostat from unipart tomorrow and I'll fit it Friday.
Fingers crossed it works.
It might be the belt on the water pump slipping, or a broken water pump but i doubt it.
I get a new thermostat from unipart tomorrow and I'll fit it Friday.
Fingers crossed it works.
It might be the belt on the water pump slipping, or a broken water pump but i doubt it.
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Re: Temperature rise and then suddenly goes back to normal?
Seems it may just need a bleed.
New thermostat and a good bleed. This is a great how to:
http://www.lovehorsepower.com/MR2_Docs/ ... system.htm
New thermostat and a good bleed. This is a great how to:
http://www.lovehorsepower.com/MR2_Docs/ ... system.htm
Re: Temperature rise and then suddenly goes back to normal?
moscoworbust wrote:
It might be the belt on the water pump slipping, or a broken water pump but i doubt it.
There is no way the belt can slip, it drives the cams too. If it was the water pump you would see lots of water under the car
Designer for turbo set ups on F1 cars, and Nitrous Oxide Systems of the USA in the 80s
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Re: Temperature rise and then suddenly goes back to normal?
bobhatton wrote:moscoworbust wrote:
It might be the belt on the water pump slipping, or a broken water pump but i doubt it.
There is no way the belt can slip, it drives the cams too. If it was the water pump you would see lots of water under the car
cheers
Re: Temperature rise and then suddenly goes back to normal?
head gasket, thats exactly the what happened to me, Temp gauge used to shoot to the top, then back down to the norm. I had no other signs of hg failure .
Re: Temperature rise and then suddenly goes back to normal?
id agree with others re H/G, but check Water pump...
My heater went hot, cold for days then gauge went through roof, H/G went, when repaired found pump had failed.
if your doing the job you may as well replace it while its apart.
My heater went hot, cold for days then gauge went through roof, H/G went, when repaired found pump had failed.
if your doing the job you may as well replace it while its apart.
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Re: Temperature rise and then suddenly goes back to normal?
What?
You would replace the head gasket before replacing the thermostat and bleeding the system?
I'm fitting the new downpipe/exhaust and intercooler now. When they are fitted I'll bleed the system and see what happens. I have already fitted a new thermostat.
I can't believe you would fit a HG before checking the more simple things.
You would replace the head gasket before replacing the thermostat and bleeding the system?
I'm fitting the new downpipe/exhaust and intercooler now. When they are fitted I'll bleed the system and see what happens. I have already fitted a new thermostat.
I can't believe you would fit a HG before checking the more simple things.
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Re: Temperature rise and then suddenly goes back to normal?
Unbelievably, this happened to me today, I think.
Temp rose slowly. I noticed at about 75% on the meter, and it rose very slowly from there to 3 dashes under full when I parked it and turned it off. Opened engine bay, no signs. Let it cool and drove home as I was only a minute away. Left the car and used the other.
On the drive home, the temp dropped back to normal.
Sounds like HG right... Will try thermostat and coolant top up first.
Temp rose slowly. I noticed at about 75% on the meter, and it rose very slowly from there to 3 dashes under full when I parked it and turned it off. Opened engine bay, no signs. Let it cool and drove home as I was only a minute away. Left the car and used the other.
On the drive home, the temp dropped back to normal.
Sounds like HG right... Will try thermostat and coolant top up first.
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Re: Temperature rise and then suddenly goes back to normal?
I was hoping to top up the coolant today but i ran into problems removing th downpipe.
I need to install the new intercooler/exhaust and downpipe before I can run it.
The temp rose at the same rate from 0 to full.
If it had just smashed up to full I would think HG. But as it went up uniformly it was if the thermostat just didn't open.
I've read enough posts on forums describing this and they just needed a bleed.
Here's hoping
I need to install the new intercooler/exhaust and downpipe before I can run it.
The temp rose at the same rate from 0 to full.
If it had just smashed up to full I would think HG. But as it went up uniformly it was if the thermostat just didn't open.
I've read enough posts on forums describing this and they just needed a bleed.
Here's hoping
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Re: Temperature rise and then suddenly goes back to normal?
Have you tried testing by starting from cold and feeling the rad pipe that runs through front bulkhead to radiator? Apparently of it warms gently, your thermostat is gone, as you'd expect it to warm suddenly.
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Re: Temperature rise and then suddenly goes back to normal?
Can't start it at the moment, as I said.
I put a new thermostat in anyway as I had everything out anyway for the downpipe install.
I'll check it.
I put a new thermostat in anyway as I had everything out anyway for the downpipe install.
I'll check it.
Re: Temperature rise and then suddenly goes back to normal?
sounds like thermostat