magic missing coolant

[MadcapMagician]

Hi guys. I need some advice, for a change….

The monster is drinking water like a whale shark!

I’ve just had a new radiator fitted cos the old one was leaking from the top seals.

Now, anytime I drive, I need to top up the expansion tank before I go anywhere and check (and maybe top up) the coolant filler cap, too.

After a few hours of being left to cool down, the expansion tank will need filling again.

With the engine running, I can see no bubbles or anything wrong-looking in the expansion tank. I did an oil change yesterday and the oil that came out looked like one would expect, with no hints of mayonnaise. The heater works fine, too.

I’m stumped!

Could it be a cracked head or knackered head gasket? Surely I’d see something obvious, though, if it were either of these…? Like I said, there’s no bubbles in the expansion tank or emulsified oil in the engine.

Could it be something simple, like an air lock? If so, how do I shift it?

In true Penelope Pitstop style….Haylp! Haylp!

[Sancho]

When you say 'top up the expansion tank', how much are you putting in there? All the way to the top?

[MadcapMagician]

Yes.

If I don't, by the time I get anywhere, if I have to sit with the engine idling, it starts to overheat because there's not enough water left in the rad.

[Sancho]

First, check that there are no obvious leaks, particularly that the hoses have been fitted to the new rad properly.

Second, change your rad cap.

Third, get the air out by leaving the rad cap off over night and topping up in the morning a few times.

Fourth, if all else fails, get the coolant checked for combustion gases.

[MadcapMagician]

First, check that there are no obvious leaks, particularly that the hoses have been fitted to the new rad properly.

Yup; done that.

Second, change your rad cap.

Well, it's definitely not leaking from the rad cap. Do I still need to change it?

Third, get the air out by leaving the rad cap off over night and topping up in the morning a few times.

Is that all it takes?

Fourth, if all else fails, get the coolant checked for combustion gases.

Does that need to be done by a specialist? Is it a quick job? How much should I expect to pay?

[Sancho]

It might be that your rad cap is jammed down and not letting pressure out, so coolant is being pushed out of the expansion tank.

Burping the cooling system is a PITA but the easiest way is to do it as stated as long as you don't mind the commitment in terms of time. Put the rad cap on the driver's seat so you don't forget about it. Putting all the heaters on hot and running the engine with the cap off until it gets up to temperature will help too.

Checking the coolant is a very quick and cheap job. Pretty much any garage can do it and it'll be £15-20 or something.

[MadcapMagician]

OK, cool.

I'm assuming that checking the coolant is what's done to determine whether the gasket's gone, right? Will it show up a cracked head, too?

[Sancho]

OK, cool.

I'm assuming that checking the coolant is what's done to determine whether the gasket's gone, right? Will it show up a cracked head, too?

It will show up either, but it's very unlikely to be the gasket that's gone - they seem to be tougher than the heads

[stormforce]

going by what you have said your topping the expansion bottle right up which you shouldn't be doing anyway.
Top the expansion bottle up to about half way.
Take the rad cap off and start the engine and set the front and rear heaters ti hot and put on full.
Gradually top up via the rad cap till the air is out.
Once you think the air is out refit the rad cap and take for a drive.
Allow to cool and then reck the coolant via the rad cap.
Just a thought tho have you had a body lift done and not lowered the radiator by any chance

[MadcapMagician]

rear heater

You mean the one on the rear of the central console?

Just a thought tho have you had a body lift done and not lowered the radiator by any chance

Nope. Rear shocks only.

[stormforce]

[quote=MadcapMagician;509110]You mean the one on the rear of the central console?quote]
yea that one.
The other thing that may be causing it is if the rear heater don't get hot then the pipes may be blocked in which you'll need to get under the truck and take the pipes off from the bottom of the rear matrix and get them cleaned out

[MadcapMagician]

Ok, thanks.

In all honesty, how likely is it to be the head?

[Sancho]

50:50 at the moment.

[stormforce]

i wouldn't like to say if it is the head but there is a possibility it could be.
I would start off by fitting a new rad cap and thermostat and then burp the cooling system to get the air out by doing what i said just now.
Go for the easist and cheapest way first and then the last choice will be the head

[MadcapMagician]

50:50 at the moment.

Woe is me.