Well, I’ve had this probLem after bringing my car out after the winter and basically it gets up to normal temp when littering around when warming up, say about 86c.
If I then give it a bootful and bring the revs over 4krpm up to 6k or more then the temperature plummets - and keeps plummeting until I stop honing and drive under 4krpm.
It really chunks down - 86…84…80…77…72…70…blank…rev limiter.
So - I took my car to stratstones in Leicester (under warranty) and they replaced the thermostat. Picked it up and same again, not really changed anything.
So - what the hell could cause this? I agreed that their diagnosis was probably right - a weak spring in the thermostat - could replacement part be faulty or incorrect?
Really frustrating as you can imagine and clearly I dont want to give it some beans when I know the engine is being flooded with cold water!!
Car is back at the garage again but just wanted opinions
I haven’t changed the thermostat yet, can’t see the point in changing it for it to go 6 months down the line. Looking to source an after market thermostat without the rubber centre piece.
It’s more apparent on cold days, though as per the above thread it doesn’t do it too badly now. Lowest it has gone recently is 75.
Seems like the thermostat is closed to start with, then just stays open after you are up to temperature, so then the rad over cools the water and you drop back below 82 degrees, I still think it is the stat.
I may be wrong, but i thought that the thermostat goes wide open when you’re on second cam. Even when the water temps are not that high. with an uprated rad, you will overcool the water when on second cam and in cool air.
Mine dropped a bit with the standard rad,
but now with an aluminium one, I couldn’t get the water temps higher than 80�C on track at Spa, in 10-12�C air temps.
Could be, mine does not go below 75 so I am not really worried. I put it down to the triple pass rad and de cat. Temps are stable until u floor it and I have only noticed it in cool air.
Thermostats work as Ade says - closed when cold, but start opening when the temp rises allowing the water to flow around the rad.
The fact the problem happens at high rpm could suggest a broken water pump. If the blades on the water pump are broken, coolant might not be sufficiently circulating around the car when at the lower rev range. The thermostat could be open, but no water making it to the rad until high rpm is reached. This also happens if you get an airlock in the system. Easy test is to leave the car idling for 10-15 minutes to get up to temp, and then check if the front rad is getting warm.
I’ve got triple pass proalloy rad and never had this problem.
[quote=N17VES]Thermostats work as Ade says - closed when cold, but start opening when the temp rises allowing the water to flow around the rad.
The fact the problem happens at high rpm could suggest a broken water pump. If the blades on the water pump are broken, coolant might not be sufficiently circulating around the car when at the lower rev range. The thermostat could be open, but no water making it to the rad until high rpm is reached. This also happens if you get an airlock in the system. Easy test is to leave the car idling for 10-15 minutes to get up to temp, and then check if the front rad is getting warm.
I’ve got triple pass proalloy rad and never had this problem. [/quote]
Sounds plausible, I wonder is there a way to measure the coolant system pressure to test the water pump?
I’ve measured the temp of the rad, it was something like 75 C in and high 60’s C out?
If so just pop it in a pan and observe it a FEW times while heating and COOLING the water … make sure it shuts properly and not on the skew… very unlikely that the new one wil be faulty too though … also if a rubber seal is used make sure it is fitted…sometimes junior mechanics are left to do the easier jobs ?
At least you have the safety of a warranty thankfully …keep us posted .
maybe its a TADTS?