Hello,

I am a new member. I'm excited to have purchased my first Rover a black 1996 Discovery I with a 4.0 with only 109,000 miles!!! Unfortunately, after having purchased it two days ago I noticed today that the coolant temps are reaching 235 degrees. I read the coolant temperature with my OBD scanner tool. When I start the car it idles low (around 500rpms) then it goes up to 800 rpms after 8 minutes or so. The coolant is at the appropriate level and doesen't seem to be leaking. When I drive it on the highway with the heater on the temps go down to 195 degrees. I am completely bummed out because I have read horror stories about the slipped sleeves, cracked block, etc. I'm getting a misfire code from cylinder 4. Does it sound like bad news for me or could it be something else?


Thank you for the help, and I apologize for starting my first post like this.

 

Welcome and bummer. Not uncommon for new members with new rides posting on problems, it's the norm.

First, the likelihood of you having a slipped liner or cracked block is low. You may have a bad plug wire on 4 so try swapping them around and see if the misfire follows the wire. You may also have a cracked coil post grounding out under the wire boot or a bad plug, remove the plug and take a look at it. If it's wet, oil soaked, fuel soaked and doesn't look like any of the adjacent I'd like to see a pic of it.

The radiator may have buildup which slows it's cooling ability when not moving or slow moving. That would be my first check, take out the bung on passenger side, side tank and shine a light in..... whaddya see?

As far as idle, it's pretty common for the Idle Air Control Valve to have carbon buildup. That requires a cleaning of the bore seat and pintle of the solenoid. Easy. Check your PCV on the passenger side valve cover, make sure it's whole and not occluded too. You bought a hand me down that came with baggage.

 

Thank you ihscouts! I appreciate your time and lengthy reply. I will try to get you a picture asap. I think your diagnosis is spot on about the plug wires because I was checking the engine codes and they all deal with cylinder 4. The codes are:

P1204
P0204
P1191
P0304
P1316
P1508

 

You also have two codes on injector 4........ winner winner chicken dinner! This link will give the LR item specifics that will help you track down your issues; Land Rover ? OBD/OBD2 Trouble Codes

Also in our tech section there is a link to download the "Rave" which is the Service Manual, lots of goodies including electrical diagrams with wire color codes which if you can understand how to use save a bunch of time.

Good luck and keep posting questions and updates.

Also I just want to add that once you get the bugs out of these (prior neglect) they are reliable as any other vehicle if not moreso, all depends on the wrench behind the wheel.

 

If your truck is not consuming/burning coolant start with a look in the radiator and drain/flush/refill with fresh green if it looks less than stellar. Change the thermostat because it is cheep and easy. Move on to viscous fan clutch next. They tend to wear out around 100-120k (or sooner). Plenty of threads about fan clutches, which you can use, and best results (I found stock worked best and was worth the extra $30 but many will differ on this point).

 

Thanks for chiming in WaltNYC. It is not losing coolant so I guess my next step will be to change the thermostat and then flush the radiator at the same time even though the coolant looks very clean. Good news, my Rover is down to 3 codes now. It's strange but cylinder five (5) spark plug cable was disconnected from the spark plug It definitely runs a little better now that I connected it back (duh) but I have to sort out the idle issue now and the injector issue on cylinder 4. I also noticed the heater hoses have been bypassed and there is a direct hose connecting the lines now. Sorry for the sideways picture, I'm not very computer savvy. I was looking to purchase this t-stat:
Stant 45358 SuperStat Thermostat - 180 Degrees Fahrenheit

https://www.amazon.com/dp/B000C848Q2/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=ZYJ0 YLYI7NY&coliid=I1LNWY6HKQFASL

Do you guys recommend this one and do I need to purchase anything else to make it work?

The codes I have now are:

P0204
P1191
P1204

Thanks again guys

 

Go with a Stant 45858, it has the jiggle pin. RockAuto has them for about $5.00, or.....>


https://www.amazon.com/Stant-45858-S...keywords=45858


And you will need a gasket. OE is # ERR2429G

 

Prior owner likely added the bypass because of a leaky heater core. Much cheaper than fixing it.

In Miami you don't have to worry about that too much.

Stant 45858 is the one you want.

May also consider some new wires and plugs.

I run the NGK BPR6ES https://www.amazon.com/dp/B000A8OW9M...9LT65KCE&psc=1

And Kingsborne wires (8mm option)...
Spark Plug Wires for Defender, Discovery and Range Rover

 

Quick question, I pulled the front passenger side carpet and I noticed there was some rust on the floor pan that extends to the door sill. The floor pan was still moist. Do you think this could be the heater core or is it more likely that it could be the AC leaking? My AC button is faulty (does not turn on), the blower works. I know the previous owner was able to get it to turn on and the compressor started spinning but now I can't get the button to work.

 

Given that your heater core has been bypassed I doubt the moisture is coming from there. A/C is more likely.