Overheating

[Drawfiler]

My 2.2 engine will overheat if left on tick over for some time, the two fans, thermostat pressure cap and thermal switch all work ok. Rad has been flushed clear. My question is=is it worth taking out the thermostat to improve water flow?

[soldave]

I certainly wouldn't remove the thermostat. What temperature is the thermostat opening at, and is it opening fully? The stock system works so if it was me I'd be trying to find out why it's not operating as intended.

[Angus553]

Have read somewhere that although this can be a short term fix on some engines, the 907 doesnt appreciate this being done. It doesnt like water unless its mixed 50/50 with antifreeze.  If taking out the thermostat  I would replace it and see if this fixes the issue or atleast test the current thermostat is working properly,eg as soldave says is it opening fully at the correct temperature.

[Painterdave]

S&j sports cars do a summer themastat and a winter one 

[dave excell]

My Excel did overheat with the original rad, even though it was flushed and clean. I had a 4 core rad built into the standard headers and the problem was sorted. Later I fitted a new alloy 3 core rad from China and it gives no problems either, except the hose unions were a bigger diameter and gave difficulty fitting the hoses. it will idle for hours with no problem. Make sure the block is not sludged up, which can happen. Cleaning with with 'rad flush' may help otherwise its a dismantle the engine job.

[jep]

I assume you have tested for head gasket failure?

Justin

 

[exeterjeep]

My first elite did overheat a bit, garage diagnosed the wrong thermostat was fitted.

[jep]

Check water pump belt, I recall it can become loose if power steering pump comes loose....I certainly had an issue on mine but I forget the technical details.

Justin 

 

 

 

 

 

[Escape]

Never leave the thermostat out! When I got my Ecxel, it didn't have a thermostat fitted and that actually caused it to run hot. The thermostat, like on most engine, doesn't just open the flow to the radiator but also closes off the bypass. Without a thermostat fitted, the easiest way will always be though the bypass so you'll get limited flow through the radiator and possible overheating.

As Justin says, the power steering pump is used to tension the belt for the water pump. If too lose, flow will be limited, though I'd expect more of a problem at higher load/rpm, not idling.

If you have an IR thermometer try and get an idea of where the hot spots are. If the entire radiator is hot, it can't get rid of the heat (despite being flushed). Or there may be cold spots if some channels are clogged. If the radiator is at a lower temperature, either the water pump doesn't flow enough or the thermostat isn't opening fully. I have removed hoses from an engine that was overheating just to check the flow, but it's not the easiest test.

Regardless of the spec, all suitable thermostats should be fully open before overheating can occur and thus prevent it. 

Filip

[black eclat]

I remember an issue with overheating on my car a long time ago where the pump impeller had moved on its shaft. The gap between the block and impeller is critical, too large a gap reduces flow. The impeller is only pressed onto the shaft.

[pbharcourt]

My Elite used to overheat if stuck in a queue or running fast for any length of time.

I tried everything but to no avail and finally pulled the head off, the block was half full of rust and sludge!

After cleaning out it has never overheated again.

[Drawfiler]

Now I’m getting air/gas in the cooling with bubbles in the header tank so suspect gasket or liners, now taking head off for a look, will report back.

[Drawfiler]

Now got the head off but can’t see the problem, gasket looks sound, head and block both smooth and clean, liners look ok to me so I am going to take bits to lotusbits for advice from Mike Taylor.

[Drawfiler]

I took the head and gasket to Mike Taylor today and he found the problem, the two roll pins that stick out of the top of the block and go through the gasket then into matching holes in the head were bottoming out in the head holes. All this is because I had had the head ground so holes in the head were not deep enough to take the pins. on looking closely at the gasket he could see that there was a sign of leaking slightly on all four cylinders on the exhaust side.

I will trim back the pins and put it all together again.

[EXCEL V8]

Well done to Mike on finding that one!  How frustrating though!  The dowels are only there to locate the gasket - the holes in the head are larger in diameter than those in the block.

Pete

[Drawfiler]

It could have been a lot worse, at least the liners and rings are ok so no engine out. I will grind a bit off the pins and try the head on then check the gap between head and block.