I got about five minutes from my house yesterday and as soon as I got on the highway my 2003 disco redlined the temp gauge. I immediately shut it off and pulled to the side of the road.

Luckily, I am paranoid and carry oil, Global lifetime coolant, jumper box, etc. I let it cool, added half gallon of coolant and the temp came down to normal for a 20 mile drive.

So, I began looking for the coolant leak. There are no broken hoses or spraying. The throttle body heater gasket (my fourth, I think) has a very little bit of coolant crust starting, but there was nothing wet burning on the valve covers as in major leaks. I don't think it is the cause for it to be this low.

Truck runs great otherwise. No codes, no misfires, all maintained per Disco Mike's service. This summer, I actually did new water pump and coolant replacement, as well preventative T-stat and top radiator hoses (my bleeder screw had failed) and all appeared normal.

Truck has 115,000 miles. Dealer replaced short block under warranty around 50,000, so has no oil pump issue and had all new gaskets then.

Do you think I am looking at head gaskets or valley pan gasket? Do I just tell the shop I want a pressure test? And, before I go down that expensive road, should I be worried that this brief overheat might have damaged the block or slipped the liner?

Unfortunately, I will not be able to tackle this myself. It's 15 degrees here and I have to work outside, so will be looking for an independent shop in Allentown PA. Thanks for any advice.

 

I'm half hour north of Allentown. There's a LR dealer in Allentown.

Sure you just don't have an air bubble?

 

Thanks. I can just about see the dealership from my house but they are $$$$$$.

Might have been an air bubble, but that will mean it definitely lost coolant, as I filled it properly and was running it in warm weather all summer. It suddenly chose to overheat on a 15 degree day. Thanks again.

 

Don't panic.

A single temp spike addressed quickly is unlikely to warp the heads and cause the head gaskets to need to be replaced.

A pressure test is in order if you can't otherwise identify a leak. I recommend just keeping the coolant reservoir topped up and drive it until the weather warms up enough to do the pressure test yourself using a kit you can borrow from any of the major auto parts chain stores.

Keeping an eye on the coolant level is a good idea anyway. Watching how fast or how slowly the level goes down can tell you how big a leak you have. Plus the engine shouldn't overheat so long as coolant is in the system and circulating.

Circulating is a key word in that sentence, of course. I had a thermostat that stuck closed a couple of years ago causing a quick temp spike even though the coolant was full. That's not the evidence in your case. I also had a serp belt disintegrate causing the temp to spike quickly and blow coolant out the reservoir pressure relief tube, but that's not the case with your truck either.

Also, it sounds like you're relying on the factory temp gauge. That topic has been beat to death on this forum so I won't repeat the info here, but many of us use, love and recommend the UltraGauge to keep a more accurate eye on temps and other engine data. Check it out.

 

Are you saying that this is the first time you've had the heat on? I could see an air bubble staying in the heater core if you never used the heat, then it moves on once you finally turn on the heat.

Also a beaten to death topic, but proper bleed procedure is very important even if you think you are fine (by using the temp gauge on the dash.) Due to this issue you should at the very least perform a complete bleed procedure just to be sure you are starting from a clean slate...

 

Dave, this doesn't apply in a DII. There is no coolant valve in the heater circuit. Coolant flows through the heater core all the time regardless of the HVAC control. (Except when the heater is plugged, of course!)Passenger compartment temps are regulated by airflow control flaps (i.e."valves").

From the RAVE - "When the engine is running, coolant is constantly circulated through the heater matrix by the engine coolant pump."

and ...

"Two sets of three blend flaps, one LH and one RH, regulate the flow of air through the heater matrix and a heater matrix bypass, to control the temperature of the air leaving the heater assembly."

 

Thanks a million, mln01. That puts my mind at ease a bit. I was totally paranoid that one overheat and my truck is doomed and I'll be throwing time and money at a lost cause - Land Rover paranoia.

I am going to let an independent at least put it on a lift. Perhaps I'll be lucky and they'll spot it. I can smell some sweet ant-freeze from under the hood, so it's hitting the engine somewhere. Checking throttle body heater repeatedly shows no liquid leaks. Probably just some old dried crud from my last install.

I will look into UltraGauge! Thanks again.

 

Thanks again for the calming words. I took it to a new indy shop who did pressure test it and they said both oil and coolant are leaking from the timing cover gasket. They are around $85 an hour and six hours to do it plus parts, which sounds high - but I know it will sound more reasonable if I were laying in the snow with it on ramps in 15 degrees.

What concerns me is I called local dealer to get an idea of price. Right off the bat, they said at least $1,000 to do the gasket, and "thousands upon thousands" if I wanted to add a new timing chain to the job. Oddly, the service rep also says that this gasket does not leak coolant, so he needs to power wash it drive and charge diagnostic because the coolant must be coming from elsewhere.

I am wrong in accepting that coolant can leak from here? The independent mechanic says he pressure tested and sees it coming out. This makes sense to me. Only a LR owner counts himself lucky with a $1,000 estimate. Thanks again!

 

I paid a local shop around 800 to repair a leaking front cover gasket so I'm pretty sure they leak coolant as the puddle under my truck was green.

Keep in mind in Seattle the shop rate is over $100 and there is a 10.1% sales tax.

 

The waterpump bolts to the timing cover.
So coolant Can leak from the cover, or the waterpump.
I can't imagine paying those prices to fix it.
With the fan, alternator, ps pump, ect, out of the way, you can see how easy the water pump and cover come off.
Oil pan comes off too.
You could buy a new front cover with oil pump, timing chain,waterpump, gaskets, oil and coolant for $550, and a Saturday's labor time, depending on how fast you work.
Just gaskets and fluids, $75.
I don't like working in the cold either, but I would before I'de pay that.