Heat build up

Post by **vanzep** » Tue Nov 12, 2013 2:17 pm

Ive been battling with cooling issues for the last year or two and am planning on doing a bit more work in this area. So far ive replaced hoses, radiator, coolant, rad cap and the thermostat was changed about 3 years ago. New water pump was fitted when the timing belt was done last year.
There seems to be a build up heat under the bonnet when i do a number of short journeys in quick succession. The car is getting up to temp fine, coolant temp has always stayed at mid point in the guage, the fans are coming on fine.
Yesterday i noticed the car felt a bit sluggish and when i reved it i noticed the revs stumbled around the 400 - 700 mark so i opened the bonnet and it was red hot under there - too hot to touch anything in the bay even the strut bar was too hot to touch. The other thing is the exhaust note gets a bit louder as well

It seems to be an intermittent problem so i was thinking of replacing the coolant temp sensor at the side of the block and putting an oem thermostat in and having the cooling system flushed and new coolant put in.

Any other ideas or suggestions would be welcome.

BMCC · Post by **BMCC** » Tue Nov 12, 2013 2:41 pm

Plumb in a water temp gauge so it gives you an idea of actual coolant temp? Not that difficult to do.

Post by **vanzep** » Tue Nov 12, 2013 2:43 pm

cheers i hadnt thought of doing that - might be an idea

Post by **Merlin** » Tue Nov 12, 2013 3:16 pm

From what you said on the phone last night the OEM coolant temp gauge shows normal. So I wouldn't expect an aftermarket gauge to show anything radically different.

When my OEM gauge shows normal my aftermarket gauge reads ~80c.

IMO it sounds like a faulty thermostat. If the thermostat does not open and allow coolant to flow to the rad, the engine may not be cooled enough with short town journeys and the rad fans are doing f-all. Out on the motorway the speed you are travelling is enough to cool the engine.

Your coolant level is fine? Are you loosing any coolant?

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Nov 12, 2013 4:24 pm

What manifold are you running now, I forget

Anyway, it's a bit irrelevant, questions is, is it heat-wrapped, or open?

Post by **Merlin** » Tue Nov 12, 2013 4:37 pm

Good shout. In his absence it is a Hytech replica, so it's a beast of a manifold and unwrapped.

Post by **vanzep** » Tue Nov 12, 2013 4:58 pm

I have some titanium heat wrap to put on but the heat issue started when i had standard manifold and ive tried a few different ones since then

Mudgey · Post by **Mudgey** » Tue Nov 12, 2013 5:04 pm

If everything is too hot to touch then water is getting to your radiator. If your in traffic everything will get seriously hot, I expect your running a non standard intake and your engine is simply ingesting the hot underbonnet air. I would suggest you heat wrap your exhaust and run a cold air feed to the wheel well or infront of your radiator.

Post by **vanzep** » Tue Nov 12, 2013 8:05 pm

Ive a type S intake so fairly oem and have removed the resonator box so air is pulled up from the wheel well - there is a slot in the lower part of the bumper for more cold air but ive not put a cold air feed in there as i didnt think it necessary and as its a daily drive i didnt want anything that risked hydrolock

ive got the heat wrap for the mani so thats something i can do

BMCC · Post by **BMCC** » Tue Nov 12, 2013 8:16 pm

When the fans kick in, the dash gauge is normal but the temp gauge reads 92c. Never seen the dash gauge anything other than normal. Reason I'd stick a gauge in is simply to see if the fans kick in when they should every time. If it is an intermittent fault this will confirm. If its your imagination it will confirm that to!

Might seem a bit drastic/expensive but at least you will know.