Cooling

Trent and his Rover

Well-known member
Jun 25, 2006
124
1
95 D1, 5 speed.

This cooling profile is a new one for me. In the past, I've experienced air in the system and had to "burp" her. And I don't think that's my problem as there's no "waterfall" sounding in the dash at the heater core. As long as she's moving down the road, there's no sign of overheating. Never a temp gauge climb or water overflow, nothing to indicate a cooling problem, but waiting in line at a gas station or stop light she'll blow lots of water out her expansion tank. Her radiator is new and her thermostat is new and tested to be working as she'll open in a hot pot on the stove. I've recently rebuilt the engine and she runs nicely which had her pass her California smog test with a new engine profile. I decided to rebuild her because I wanted to pull the block and renew all its freeze plugs. They had aged and were leaking allowing air into the system which caused the "waterfall" sound.

When refilling the water back, I:
1. Lift the front up 2 feet high making the radiator the highest point.
2. Fill the radiator slowly.
2. Fill the expansion tank slowly.
3. Start engine, turn heat to HOT both sides.
4. Let engine idle until thermostat is open and have heat coming out of the heater.
5. Once air stops coming out of the radiator fill plug plug it.
6. Once the coolant level in the coolant tank stays constant replace cap.
7. Shut off engine.
8. Drive it for a day, let cool overnight, recheck coolant level, add if needed.

As I slowly fill the radiator I can see the plenum return line clearly shoot water back to the radiator thru the fill plug hole. This indicates no blockage in the system and so my opinion is that the system is free flowing. I've no idea what the problem might be and appreciate suggestions. Lastly her tachometer now reads zero and I assume the cable took a dump. Anyone know how easy/hard it is to fix? Thanks.
 

discostew

Well-known member
Sep 14, 2010
6,409
494
Northern Illinois
Two thing to check. First is the cooling fan. See if it wobbles on the shaft. See if it's moving air. If it's ok going down the road but not sitting still, you gotta figure it can't move air on its own.
The other thing is how the belt is routed. When looking at the top of the belt, in the center it should go down under the water pump. I've seen people have them routed in a way that bows over the top of it all. That's not going to work, but somehow it will fit that way.
 

Trent and his Rover

Well-known member
Jun 25, 2006
124
1
Belt routed correctly and cooling fan moving when she's in neutral and I'm adding water. So, if I understood you correctly, then all's well with the cooling fan. The AC fan however never seems to come on and not sure if that has relevance. Seems that I recall it hasn't come on for 6 or 7 years. And the AC fan on our RR hasn't come on for at least 16 yrs so maybe it isn't relevant.
 

mbrummal

Well-known member
Jan 23, 2009
2,868
8
Apex, NC
No tachometer might be the alternator going bad. The instrument cluster gets the engine speed signal from it.
 

discostew

Well-known member
Sep 14, 2010
6,409
494
Northern Illinois
Well if you say it never overheats when its going down the road and it only overheats when it's stationary. I really can't think of anything but air flow as a cause. You say it's got a new radiator. So what else is there? I guess a restriction someplace that the pump can't overcome at idle?
 

mbrummal

Well-known member
Jan 23, 2009
2,868
8
Apex, NC
If the viscous coupling is failing, the fan can still be spinning but not pulling enough air through the radiator. See how difficult it is to spin the fan by hand with the engine off. Or see how long it spins after shutting the engine off. It should have some resistance when you try to spin it and it should not spin very long after shutting the engine off.
 

discostew

Well-known member
Sep 14, 2010
6,409
494
Northern Illinois
Yes I agree with mbrummal. You say you have a Range Rover. Get them both warmed up and compare the air flow you feel in the Disco with the flow you feel in the Range. Compare the Disco to a known good cooling system.
 

best4x4

Well-known member
Mar 1, 2015
506
45
Beaumont, TX
The AC fan however never seems to come on and not sure if that has relevance. Seems that I recall it hasn't come on for 6 or 7 years. And the AC fan on our RR hasn't come on for at least 16 yrs so maybe it isn't relevant.
The twin Efan's should come on whenever the AC is on. You can use a 97-98 Corolla Efan motor's as bolt in replacements. You will just have to cut/splice the wiring harness.
 

Trent and his Rover

Well-known member
Jun 25, 2006
124
1
I've ordered the vc on the chance that it's my culprit. Not sure if it's good or bad as the turns freely and easily, both ways, with the engine off. The RR also turns freely but with a bit more resistance.

As for tach, the alt is good so I'm assuming it's the cable. Anyone know its procedure?

Thanks, -Trent
 

discostew

Well-known member
Sep 14, 2010
6,409
494
Northern Illinois
I've ordered the vc on the chance that it's my culprit. Not sure if it's good or bad as the turns freely and easily, both ways, with the engine off. The RR also turns freely but with a bit more resistance.

As for tach, the alt is good so I'm assuming it's the cable. Anyone know its procedure?

Thanks, -Trent

What cable? It can be charging but not sending a tack signal.
 

Trent and his Rover

Well-known member
Jun 25, 2006
124
1
White tach/alt wire was an easy fix, just plugged it in. Cooling is still a problem. Installed a new VC fan but to no avail. As I fill the radiator I can see the plenum return line clearly shoot water back to the radiator thru the fill plug hole. This indicates no blockage in the system and so my opinion is that the system is free flowing.

As previously stated:

In the past, I've experienced air in the system and had to "burp" her. And I don't think that's my problem as there's no "waterfall" sounding in the dash at the heater core. As long as she's moving down the road, there's no sign of overheating. Never a temp gauge climb or water overflow, nothing to indicate a cooling problem, but waiting in line at a gas station or stop light she'll blow lots of water out her expansion tank. Her radiator is new and her thermostat is new and tested to be working as she'll open in a hot pot on the stove. I've recently rebuilt the engine and she runs nicely which had her pass her California smog test with a new engine profile. I decided to rebuild her because I wanted to pull the block and renew all its freeze plugs. They had aged and were leaking allowing air into the system which caused the "waterfall" sound.

When refilling the water back, I:
1. Lift the front up 2 feet high making the radiator the highest point.
2. Fill the radiator slowly.
2. Fill the expansion tank slowly.
3. Start engine, turn heat to HOT both sides.
4. Let engine idle until thermostat is open and have heat coming out of the heater.
5. Once air stops coming out of the radiator fill plug plug it.
6. Once the coolant level in the coolant tank stays constant replace cap.
7. Shut off engine.
8. Drive it for a day, let cool overnight, recheck coolant level, add if needed

Anyone have a idea how to run this one down? Thanks.
 

Va_Disco

Well-known member
Dec 22, 2014
106
6
Hampton Roads, Va.
Did you ever replace the electric cooling fans for the AC condenser? I had this same problem and replaced the two fans and the problem went away. But Like you it was the last thing I did and I replaced everything else first because my fans would work intermittently.
 

Trent and his Rover

Well-known member
Jun 25, 2006
124
1
Thanks Va_Disco. Not sure just how they're designed to work. Aren't AC fans only employed by the AC? Or are they double duty and also designed to keep the coolant temp level low? Honestly don't think they've worked for some years on both the D1 or RR. Saw a youtube vid where it was suggested to replace the AC fan brushes, anyone know a source for such brushes?
 

bearskinrug

Active member
Nov 19, 2012
34
0
Vegas
Thanks Va_Disco. Not sure just how they're designed to work. Aren't AC fans only employed by the AC? Or are they double duty and also designed to keep the coolant temp level low? Honestly don't think they've worked for some years on both the D1 or RR. Saw a youtube vid where it was suggested to replace the AC fan brushes, anyone know a source for such brushes?

I have a similar problem. I've heard my AC fans come on once. That was after driving my 98 like a maniac to something I was late for. They were roaring after I parked it and shut the engine off. Is there a temp sensor for these things that could be going bad?
 

Levi

Well-known member
Jul 27, 2004
555
19
Cheyenne, WY
Did you check for debris between the radiator and AC coils? This was my problem the first time I had this problem. I washed out all sorts of crap and it was fine after.

My car stated to get hot today (just over half up on the temp gauge) working hard over 8,000 ft. I shut the AC off and it immediately cooled back down. Checked the fan and it spun 1/3 turn hot so I replaced it and sprayed out the radiator when I had it off but didn't get much out. Took it for a run with both ACs on and it stayed less than half up the temp gauge after.