Hxn2Cnda

Hello again,

My Express 3500 is having a problem where it lights up the overheating warning (around 125 degrees) as I’m setting off.

The slower I speed up the less likely I get the warning light pop up. There is a faint smell of burning coolant (I think that’s what it is) but the reservoir seems good and I’ve not noticed any leaks.

any ideas?

Thanks!

mountainmanjoe

Please make sure you always post your vehicle info. Definitely the year, and the engine would help too. Thanks.

lots of things can cause overheating.
Bad pressure cap.
Bad thermostat.
Bad pump
Not enough coolant
Air in the coolant
Bad head gasket
Bad temperature sensor or wiring.
blockage in the radiator


Coolant smell would indicate leak, which could be anywhere. Radiator, hoses, heater core, water pump, ....
There are leak detection kits on Amazon.

Hxn2Cnda

Whoops! My bad.

It’s a 4.8l Petrol, 2007. It’s actually a short school bus.

Thank you for your input. I’m going to start with looking harder for a leak. Hopefully just some hose I can replace.

Hxn2Cnda

Had a look this morning. The only place I can see any sort of liquid in the engine bay is from the back of the radiator.

sorry for the bad photo.


Would you recommend taking straight to a garage or trying a stop leak product?

Thank you again.

mountainmanjoe

no definitely no stop leak product. You could end up worse off than before.

That does look like a radiator leak. It could be a bad fitting,bad hose, or cracked tank, etc....
You need to pinpoint where it's coming from.

Call your parts stores and see if they have a loaner radiator pressure tester kit.
Or get a leak detection kit like I mentioned before.

Rednucleus

Probably low on coolant too; check your radiator (not reservoir) when it's cold.

Hxn2Cnda

My old man told me never to use them Stop Leak products, just making sure his advice was sound.

I checked the Rad when it was cool, pretty empty. Topped it up and took it straight to a garage.

They booked me in for this morning and the rad has been replaced.

Thanks for your help guys.