coolant issues please help

[LLamaFarm]

i did a search but it didnt really answer anything for me so hopefuly someone can help

my 325 m20 runs at 3/4 hot so theres an issue somewhere that ive been trying to find, the heaters blow hot air so i assume the water pump is circulating, the bottom of radiator is cold, the top is warm, so is it the thermostat and the hoses are just hot from the water in engine/surrounding area, or is the radiator blocked? looks relitivly new the rad does so im suspecting the stat but the warm hoses have got be confused

thanks

[mattycoops43]

Faulty gauge? Is it actually too hot? does it smell hot? All sounds normal to me apart from the gauge.

[LLamaFarm]

the radiator should be at least warm though not stone cold?

[mattycoops43]

You said the bottom is cold, the top is warm.

[LLamaFarm]

yea it is, the top rail is hot and the bottom/most of it is cold is this normal then? the guage never really goes over 3/4 maybe a nats over sometimes, i replaced the guage sensor a while back as it didnt work could i have a crappy sensor?

[Brianmoooore]

Check the small brass nut on the back of the cluster (or lack of it) before you get too involved.

[Mikey_Boy]

+1 - this sounds like a gauge issue rather than anything really wrong...

[LLamaFarm]

thanks for help, i checked the nut and thats ok, maybe its the sensor, i believe its from a 320 and mines a 325 if that makes a difference?

im kinda thinking the thermostat is opening as i commute 17 miles odd and it dont go over 3/4??? it would need to open going that far and have some sort of cooling.

[LLamaFarm]

bumpty mcbumpten

[Brianmoooore]

Sensors are all the same.
If the gauge reading is stable when the car is up to temp., then IF it is overheating, and not a gauge fault, it can only be a thermostat problem.
Any indication that it is actually overheating when you switch the engine off, such as boiling noises?

[LLamaFarm]

all looks and sounds pretty normal, ill swap the thermostat tomorrow just in case

Thanks Brian your a legend

[mrLEE30]

You may even find there is no thermostat.

[LLamaFarm]

update incase anyone else has same issues,

was the thermostat sticking slightly, still opened in boiling water but when testing against new one didnt open as far, car runs better, on a second note the hose decided to split on the housing and was a bitch to remove so for others doing a search as i didnt find much heres the how too simple way

if its a m20 its simple if you know how, dont need to take inlet off at all either, first obvioulsy all pipes off and remove the temp guage sensor, 2nd loosen the bolts holding housing on, 3rd unclip the plastic rail next to the fuel rail should pull off, be gentle though. 4th there are four bolts mounting the metal fuel rail on undo theese and it should lift up enough to enable you to remove the housing. - stupid design imo

eurocar parts do a nice shiney new housing for £30 delivered

haynes manual on suggesting removing half the car is all horse crap and shouldnt be followed unless you want to spend all day doing it.

thanks for all the help everyone