04 Discovery 2

boulder4x4

Active member
Callsign: 2X4
Sep 17, 2017
44
1
Colorado
So here's the deal, maybe this will help someone else with the same problem. A while back I wrote a post asking for help with a problem of air getting back in my cooling system, anytime the rover was off camber the slightest bit air would rush to the top of the heater core.. I finally figured out why it kept having the "waterfall" sound behind the dash. The coolant level was too low. it did not look low and was always at the correct level. (never overheated) The fix for me... I started the rover from a cold start with the overflow bottle in place and the cap off. I topped it off up to the neck, as the coolant crept up to the top I would open and hold the throttle in place and the coolant would be sucked down by the engine. I did this until 4k rpm, The whole process took less than 5 min. (My rover did not get to operating temp during this time) with the rpm's at 4k I used one hand to hold the throttle open and one to put the overflow cap back on. Now I have no issues at all.




cheers.
 

boulder4x4

Active member
Callsign: 2X4
Sep 17, 2017
44
1
Colorado
Correct... but this time I did it correctly and not the conventional way...I thought I was doing it the right way all along with the overflow tank on or above the battery box.
this is my 5th rover btw
 

boulder4x4

Active member
Callsign: 2X4
Sep 17, 2017
44
1
Colorado
Well, I have a fully rebuilt 4.6 with tophat sleeves a mild cam, and the in-line 180 thermostat....
running the dex cool coolant.
 

Swedjen2

Well-known member
Sep 12, 2018
75
5
California
Oh, yeah? What cam?

As far as coolant, here is some interesting info:

"In the 1990s GM introduced an engine coolant called Dexcool. It's supposed to last 5 years or 150,000 miles but there have been problems with this coolant. Cooling systems that use Dexcool exhibit more acid buildup and rust in the system when the coolant level gets low and oxygen is allowed to enter the system. The acid eats away at head gaskets and intake gaskets. Rust builds up in the system, inhibiting coolant flow, which causes overheating.

Overall, numerous cooling system problems have been attributed to the use of this controversial product, although GM firmly stands behind it. There were class action suits against GM on this issue, and GM reached settlement agreements with some owners beginning in 2008.

So what are the guidelines on maintaining engine coolant?
Here's the bottom line when it comes to cooling system maintenance. Whether you are running Dexcool (the orange stuff) or ethylene glycol (the green stuff), inspect the coolant level and the condition/protection of the coolant at every oil change. In addition, completely flush and refill the system every two years or 25,000 miles, whichever comes first. These actions will avert the problems associated with Dexcool or any other coolant product."

Bob's your uncle.
 

JUKE179r

Well-known member
Sep 14, 2016
209
6
Suffolk, England
Over here the Brits are serious about continuously using Dexcool in their Land Rovers.
They think I'm crazy for having Zerex coolant in my Disco's V8.
 
Last edited:

jastutte

Well-known member
Nov 10, 2009
208
3
Over here the Brits are serious about continuously using Dexcool in their Land Rovers.
They think I'm crazy for having Zerex coolant in my Disco's V8.
is that mainly in diesel engines?

i'm assuming they don't have the overheating and corrosion issues we have had with the Dexcool in the gasoline engines?