So I had my first heart stopping moment today driving to work where the temperature gauge nearly hit the red when I slowed......"eekkk" I thought, and starting think "gosh, I wonder what that could be". As i moved more with the traffic it went back to normal.

However, as the engine seemed to be having a warm moment, the cabin wasn't even when I stuck it on full heat, inside was still like a fridge.

So something is a miss.

I'm thinking blocked/stuffed thermostat, replace, fill, bleed, and all should be good. Oh and this seems like a good idea to find the coolant leak as well!

Can you good folks tell me yup, your right, or nah your waaaaay off the mark.

Thanks

 

It sounds like there are air bubbles in the cooling system. Bleed the system and that should take care of these problems.

 

sound like the heater core is filled with air, but were did the coolant go? time to pressure test your system for leaks

 

Engine warm/hot, but no heat inside the cab is a classic sign of failing water pump too.

 

This is true. It's probably best to check the whole cooling system. Better safe than sorry with such a critical system.

 

so i've been under the bonnet today and checked the thermostat, works fine and refilled and got all the air out of the system. Turned the engine on and left running for about 10 minutes, not a jot to signal an overheating engine. Then, I noticed slight water leak onto the engine and found a small hole in the manifold outlet pipe.

you reckon i can fix this, or I need to replace it?

 

If it came threw in one spot it is likley ready to come threw some place else too.

 

Is it the manifold heater pipe that is leaking? Or is it the metal pipe coming out of the lower intake manifold? In either case, I would replace the bad part. Like Drowssap said, if it's got a hole in one spot, there could be several weak spots that could blow out at any time and leave you stranded. Or worse, overheat the engine and then you run the risk of much worse problems.

 

I would check your electric fan and viscous clutch, as well. Your original post said it spiked at a stop (no air flow without electric fan or proper engagement of viscous clutch) but went back down when you moved (achieved air flow.)

Even a perfect cooling system and brand new radiator cannot radiate the heat anywhere without air flow.