Jimny overheating

I have recently bought a 2004 jimny but am having some overheating problems. We have replaced the water pump, thermostat and flushed the system. Also got a new rad cap on the way. Anyone have any ideas of what could cause this? 

doesnt look like the head gasket as oil cap isn’t gummy but have but a steel seal in to stop any new breakages in it. 

 

Is it loosing coolant or are the levels staying about the same?

What about the radiator, is that getting hot? What about air flow over the radiator, it it blocked or has the fan coupling failed?

Does the heater work?

All because you are not seeing water in the oil you might have a cylinder to water way gasket leak, the way to check is have a look at the plugs or is the water system getting pressurised?

Assuming you are in the UK it shouldn’t be over heating at this time of the year.

Thank you for your reply.

Yes located in the uk south east.

Coolant levels are staying around the same with it. It gets hot and the expansion bottle starts to boil. Radiator is getting hot at the top but not really at the bottom( top very hot to touch bottom cold slightly warm).

Spark Plugs are new replaced them last week along with new oil, oil filter, air filter and fresh coolant.

Heater was working it did stop for a little then started again.

Hot water enters the radiator at the top and exits from the bottom, if the top is boiling and the bottom cold it sounds like you have poor or no circulation.

If you have replaced the pump, always assuming it is turning correctly on the drive belt, it points to a water blockage somewhere, perhaps the radiator, a pipe or a water channel is blocked?

The heater water is taken before the thermostat, interesting it wasn’t working at one stage, but now is.

I wonder if the previous owner had a leak and chucked a load of rad weld in that has blocked the system?

Robin

The reason for asking about the plugs, if you have a leak from water jacket to cylinder, one plug will be washed clean, whilst the others will have the normal levels of deposits on them.

If it was your rad cap, I would expect you would be loosing coolant and there would be condensation around the cap although if the water in the expansion tank is boiling you are probably seeing some condensation anyway.

Robin

100% sounds like a blocked radiator best bet is to remove and flush with water if you fill from top it should empty as fast as you fill, you might be able to get away with back flushing it from the bottom if thats the case

Sorry should have mentioned we flushed the rad with the hose with the pipes off and it was gushing out fast. Have tried to flush as much of the system as possible.

When we changed the thermostat the old one was gone wouldn’t open at all and the new one is a lot better but it could still be blocked in the pipes.

What’s the best way to flush the pipes and Everything out the system.

Thank you for your help.

On the subject of the heater it was working before we replaced the water pump and thermostat.