Help, please!!! Still overheating?????

Finally!
2.5D n/a Engine all back together, and sounding sooooooooooo sweet!
But, overheating? :evil:
new head & head gasket, hoses checked, sender new-correct one, temp gauge-reading correct, water pump working, radiator new-correct one, expansion bottle new-correct one, thermostat new-correct one, heating matrix checked, flow of water checked, with no thermostat checked.

Might be totally off beam here but have you checked the pump timing? A seriously out timing can cause overheating.
Good luck
Dave

Hi,

I'll have a look at that in the morning. Many thanks, Mark

What do you mean it is overheating?

Is is BOILING UP and blowing steam all over the place?

Or is the temp gauge just reading high?

CharlesY

Hi,

The hoses get very hot. Tried it without a thermostat, still gets hot.

Temp gauge, thermostat and sender are working correctly.

Thanks, Mark

Hello,
Many thanks for your replies.

Just come back from the garage;
On tick-over reads normal, give her something to do, straight into red. Running so hot, you can't touch the rad/hoses etc.

The engine sounds so sweet. So doubtful fuel, and oil is good. The correct thermostat/sender are in, and have been checked and are working. Guage working. Water pump seems to pump water in right direction. Hoses getting hot, and water seems to be flowing.

New rad coming out to be thoroughly checked over, then water pump to ensure all fins are ok. If not, then, the head will have to come off, gasket/ports/capillaries etc checked. It's a new head (defender type, unable to get a series 111 one), so the 2.5D block is different to the head.

We'll see! thanks again, Mark

I ask AGAIN ...... IS IT BOILING UP and making steam and gurgling boiling noises?

If not, it is almost certainly not too hot.

An engine like that will feed water at about NINETY degrees Celsius (bloody hot and not far short of boiling) out of the top hose and into the radiator. Water that hot will also pass the water pump's by-pass pipe.

Before you invest a lot of money get and fit a capillary type temp gauge. It's sender should fit into one of the unused tapped holes on the head at the back left corner. These gauges need no electricity and tend to tell the truth.

Hi CharlesY,

Steam, and a lot of pressure when removing cap, far more than normal.

Heads off, checking gasket and for blockage both in head and block. New rads ok, as is the water pump.

We'll see.
Cheers, Mark

I second CharlesY for sure.

Failing that I'd suspect the Thermostat. New or not, it can still be faulty.
Take it off and check it's operating using the old pan of water check.

Cant see it being timing if the engine is running sweet.

Water pump obviously figures into the equation so that too should be checked regardless of whether its new or not.

Blocked pipes, loss of coolant are other possiblities and could benefit from a backflush.

Failing all that I'm stumped.
It can only really be something I've listed or what CharlesY suggests...a faulty sender.
Hot pipes mean nothing as all pipes on all engines are untouchable once they're at normal operating temperature
Wont be your head/head gasket either unless your finding water in your oil.

I had the same when I fitted my 2.5 NA, temp gauge went way off the red, yet engine never boiled, really did my head in, ran with no thermo, still did it, changed sender etc, bit better, but not right.....


Went to Halfords and bought a temp gauge, that showed the actual temp, wired it in, now shows engine running at 80 ish degrees with thermo in, so was a simple answer to a frustrating thing...

Try that, it may be either the sender or your gauge is out, def the cheap option to try first.

Many thanks again.

If a water-cooled engine REALLY overheats, the coolant will BOIL and at some pressure (set by the pressure cap on tank or radiator) the pressure cap will lift and CLOUDS OF STEAM AND BOILING WATER will be BLASTED out.

If this does not happen, it is probably OK.

You must remember it is a pressurised system, and it will build up pressure in normal operation, so if it is HOT and you undo the cap it WILL blow hot water at you, for sure, even in normal circumstances. Read the warnings on the cap, the user's manual, the Haynes Manual, etcetera.

The extra pressure stops the coolant from boiling till the temperature has gone well over 100 degrees C, and it could reach 110 degrees or more, which is VERY hot, and if you release the pressure by undoing the cap the coolant water-steam mix will practically EXPLODE out of the tank or radiator right into your face.

A good trick is this ...

The cap fits on "bayonet lugs". You push it down, turn to the right just a CLICK which stops it coming off, and then turn it about a quarter turn more. It's this last bit that sets the pressurising feature.

Fit the cap tight as normal, then without pushing down on it, turn it anti-clockwise till the cap catches the lugs and stops turning. It will not pressurise, and so it will boil sooner than normal - if it boils at all.

Now take it for a decent drive to heat it right up.

The coolant will not pressurise, so it will BOIL when it gets to 100 degrees, or a tad more if there's a lot of anti-freeze in it.

Try this and with any luck it isn't really "boiling" at all!

Thanks for all your help.

It looks like the head gasket was partially blocking a waterway on the block.

So, several types on order. Reassemble, and hopefully..........

Cheers, Mark

Hello all,

Thank you again for your help, and comments, truly grateful.

So she's back, and sounding very sweet, and with a new MOT!

Maybe it was a waterway blockage, or the head gasket not seating properly, who knows, but now drives very, very nice, and stays on the "N" even in heavy traffic.

So here's the mains things that have been renewed/changed;

Cylinder head (complete i.e. valves, stems, rods, hot spots etc)
Head/water pump/thermostat etc gaskets
Fan and shroud
Radiator
Temp sender
Glow plugs
Thermostat
Rad hoses
Fan belt

and various bit and pieces.

So driving her around gently for a couple hundred miles, and enjoying it.

All the best, Mark

Super!
Good feeling huh?