Is this a HG issue?

[tajbhambra]

Here goes fellars, see if you can help me:

Gotta an otherwise mint 1989 G 16V and a recent new heater matrix fitted.

Car seems to run hot, fan works, no air lock, but within 10 mins, oil temp up 105 and gauge 75-80% max.

not very hot air being blown into the car from heater, and fan kicks in late. lower radiator hose quite cool comparatively.

water in expansion bottle bubbles. no obvious HG issues, like mayo or white fumes. Water pump change last year.

how should I approach this problem? I had planned to sell this, but wont sell a car if there is a HG fault without disclosing first.

Cheers

[Conker]

Compression test it first, as its the cheapest option.

Could also be thermostat or a weak water pump or a blocked rad.

My 10p would be on thermostat.

[maxp]

Take it its after 10 mins driving and not 10 sitting in traffic?

If stationary 105 is okay-ish

[Alpine mike]

Compression test it first, as its the cheapest option.

Could also be thermostat or a weak water pump or a blocked rad.

My 10p would be on thermostat.

Thats what i would have said.