I'm new. New owner, know pretty much nothing about cars. Probably shouldn't have bought a Disco II. But that's besides the point. Here is the point...

Driving down the street (for about 5 min. at 35-40 mph). Stop at a light. Then accelerate at green. About 400 yards later temp says I'm overheating. I think I was on the phone so I just pulled over and shut off engine for about 5 minutes. I start it back up to check out the temp gauge, says it's normal. So I drive down the canyon, about 25 min., 65-70 mph.

I stop at a light at the bottom of the canyon. Accelerate at green. About 600 yards later temp says I'm overheating. I stop pop the hood and the coolant is boiling like crazy and coming through the lid and a little through the bleed hose. It seemed like I had read on here before to unscrew the lid and release the pressure. Every time I did that it would start to boil again like crazy and go out the lid and hose again. A lot of coolant came out. It was green as green should be. I didn't know what to do so I let it cool a while, started it up, drove 5 miles to my buddy's house (temps were normal) and there it sits with pretty much no coolant.

I know there is a problem somewhere and that needs to be addressed soon, but I just need to get it home. Main concerns now:

Can I just pour some more coolant in or is there a special procedure?

Do I need to drain or bleed before putting in more coolant?

Does it matter what coolant I put it in it?

I apologize for the newbiness of this post. I'm sure there are answers all over the forum, but I'm in somewhat of a hurry just to get this thing home.

 

You need to stop, take a breath and then consider send me your phone number before you toast that engine, I'll walk you through what to check and do.

 

Hello! Welcome to the forum.
A) Create a signature that lets everyone know what year D2 you have an how many miles.
B ) What color is the anti-freeze?
(IF ORANGE)-Drain that crap right away. That is DexCool and turns to sludge, creating over heating issues because the bottom rows of the radiator become worthless.
(If GREEN)- Perhaps you have to much anti-freeze and not enough water??
Is it leaking fluid though?? Besides the boil over hose coming from the coolant tank?
Get an ultra gauge, it will allow you to read engine codes and check the real temp of the engine. The engine temp gauge isn't accurate, its electric and read by a computer that says: cold, normal, NEW ENGINE BLOCK TIME. Its really crucial that you don't over heat these aluminum blocks because you can get a slip sleeve. Also, download the RAVE manual, this will tell you how to do everything to these D2's!
How mechanical are you?
If you ever need a shop to help, Great Basin Rovers is right in Salt Lake and they are top noch world class!

 

How many miles on your new Discovery II?

Discovery means - you'll Discover how expensive it can be II.
You'll discovery how much money you can spend - and more.

YES - you MUST stop driving it.

The boiling is air from a blown cylinder head gasket.
Sorry.
I had the same thing on my 2001 Discovery II.

Headgaskets at a garage - $2,500 or so.

You do it -
$500 or less.

Did you get this Discovery from used car dealer??
There was a reason it made it to that used car dealer..

 

Don't worry.
Once the headgaskets are replaced - all this will be OK.

Could be your thermostat too - but I doubt it.
Thermostat is only $40.

Problem is -
When temp goes to hot and light come on
and needle goes to H then headgaskets are damaged.

 

Sorry guys I forgot to add my signature. It is a 2001 disco II 100k miles. Head gaskets replaced 2k miles ago still have 10k left on the warranty from the shop (hopefully).

 

Pull that warranty out and get real familiar with it. Look for any exclusion clauses in which they could deny coverage and make sure non are present. This could be a get out of jail free card. But whatever you do, don't tell them you drove it so long after the gauge hit "overheated"

 

I don't think this is necessarily true. The coolant system is under mild pressure and thus the fluid will boil at a higher temp. When the pressure is reduced, the boiling point of the fluid decreases, allowing it to boil over at the same fluid temp as before when the system was under pressure (and not boiling). At least that's how I understood it.

 

CalcTool: Ideal gas law calculator


PV=nRT

Pressure * Volume = n (constant) R * T

Pressure * Volume
_________________ = T
n * R

So, you are correct.
But, I don't believe his cooling system is boiling from temperature.
Rather -

Air has entered from the heads
and
the coolant sensor is now bare and heating up..

yet ----
He said the heads were JUST replaced.

So, you may be right..

There should be a 50/50 of coolant / water..
Seems he may have more water in there then coolant.

Or the system just needs bleed.

I bet though it may be a botched head gasket job..

Or a blown thermostat.
Dear ghengis86

Please take a picture of your thermostat and post it..
We need to see if it looks fresh or really crummy.

TO post - go to advanced.
Use the attachment link

 

I've boiled coolant plenty of times during track days, it doesn't always mean blown headgasket.

I would check for excessive air in the system first. You'd be surprised at how many shops don't know how to properly bleed the cooling system in these trucks. Next, thermostat, fan function, and then radiator temperature.

I don't know how far from home you are, but it might be in your best interest to call a tow truck at this point.