Temperature gauge slightly past dead centre

[kapowww]

After some dramas with some coolant leaks, the mechanic finally replaced the tank cap and fixed a split on the end of a heater hose so now there's no more leaks! Very happy with that, although now I have a different problem..

Driving it back from the mechanics it was fine on the freeway, but when I hit stop-start traffic the temperature gauge would move up to halfway between the middle line and the next white line. Then every once in a while it'll fluctuate up to the next white line and then back down. I drove it to and from the city the other day and the same thing happened.. It doesn't get near the red but any fluctuation gives me a mild heart attack nowadays.

I've done a lot of searches over the past few days and tried a few things but haven't found anything which exactly matches my problem.
-Tested the fan with a roll of newspaper and it's looks strong.
-Tried bleeding a bit last night by running it to warm with the cap off.
-Heater doesn't seem to make a significant difference.

Problems:
-Refilled mainly with tap water and probably way less than a 50/50 mix of red coolant.
-I thought I did a full flush (going from green to red before bringing it back to the mechanic) and all went well, except when refilling a lot of green came out of the top radiator nipple so I let this all spill out before reconnecting the hose. Don't think sludge would've formed in a couple of days and with minimal green??
-My aircon never worked when I got it and hasn't ever really blown cold air. I don't get the book warning anymore.

So in summary the temp is slightly above dead centre and fluctuates when I stop in traffic. Any ideas?

[Tombie]

How old is the radiator core?

[kapowww]

How old is the radiator core?

I have no idea, just bought the car. I was thinking I may need it cleaned or replaced?

[p38arover]

Do NOT let it overheat. They are intolerant of overheating. That will bring you a world of grief.

[Tombie]

I would be fitting a new radiator or at the least having it cored.

Has the thermostat been replaced?
Not a bad idea either.

[kapowww]

By overheat do you mean above middle or past the H?

It wasn't doing this before the leak was fixed (in the one day I drove it lol) so not sure if it's something else.

[PeterAllen]

Try checking the return tube in the reservoir is not clogged up. Its connected to the radiator top (drivers side and small tube connects into reservoir. This can cause problems. easy to test . disconnect from radiator and see if you can easily blow through the pipe ( take cap off top up tank to allow free air flow when testing)

[kapowww]

Try checking the return tube in the reservoir is not clogged up. Its connected to the radiator top (drivers side and small tube connects into reservoir. This can cause problems. easy to test . disconnect from radiator and see if you can easily blow through the pipe ( take cap off top up tank to allow free air flow when testing)

I did that after the flush, but do you suggest I do it again?

[wayneg]

If the rad is partially blocked, once stationary you can get temp rising above normal. When all is ok my car never ventures from the 12 oclock even in extreme heat here in Perth. The Rad tanks get brittle so the chances of removal and refit are slim to zero. A new rad is about $300 on ebay and 30 mins to fit.

[FANTOM P38]

Hey Paolo
Just PM'd you re catch up - as far as radiator goes check there is no obstructions from grille thru to radiator ie mud build up etc. also make sure system is properly bleeded ( had to wonder re flush when you changed fluid and some old green stuff came out)
I have a Aussie Dessert cooler in mine now but even old radiator hardly went over centre unless very hot day until I snapped exp tank fitting and i continually seeped!
Would conside changing thermostat & check water pump & hosesalso heater hoses!
Martin

[poleonpom]

Could it be that the mechanic has not refilled the system? P38s are notorious for being difficult to refill and often need to be "burped"

[p38bedfont]

Have you checked the earths.
My temperature gauge fluctuated higher if I turned on heater, headlights, heated rear screen etc.
If the temperature gauges moves with heavy load, check earths.

[poleonpom]

You can check the temp cheaply with the Torque Pro app for smartphones. You'll also need a wireless elms plug in unit

[p38arover]

By overheat do you mean above middle or past the H?

Well, that's a difficult one. Probably past 3/4. If the almost invisible red light comes on on the dash, it's probably too hot.

Re the heater, turning it on seems to make little difference because water flows through it all the time - there is no water tap. Having said that, I've not actually checked the flow diagrams to see if water flows through the heater core when the thermostat is closed.

My radiator was severely clogged.

http://www.aulro.com/afvb/attachments/p38a-range-rover/46979d1337296785-no-heater-p38aradtopcopy9ms.jpg

[kapowww]

Thanks for all the replies guys. I burped the system again, and blew some coolant out of the return tube from the radiator when it was cold. I drove it around my suburb a bit at night, then in stop-start peak hour traffic yesterday morning and then smooth highway on the way back home and it stayed pretty much dead centre. The parallax error freaked me out a bit.

It did start rising at one point after about 35 minutes in the peak hour traffic when I arrived at my destination. It went to about halfway to the next white line but I had to run in so couldn't really test any more. I'll try to bleed it once more but there was definitely a pocket of air in there that caused the fluctuations when stationary.

Don't think there's any issues with the ground connections. The radiator could be a bit clogged too so I'll budget for a new one soon.

The green/red coolant mix is apparent now and is starting to look a bit brown (checked at night with a flashlight so need to check during the day) so I'll have to do another bloody flush and fill.

[DiscoMick]

Are you sure the correct coolant is red? I thought LRs used green. Mine certainly does.
My temperature needle never moves above about one-third, no matter what the conditions are like. Mind you, the gauge system is notorious for not giving a high reading until its too late.
A few years ago mine was obviously on the edge of failing, although it hadn't actually happened, so I had it replaced before I went to Cape York. Best thing I ever did as far as peace of mind goes.
Have you checked the thermostat? A replacement could be a cheap fix if that is the problem.
As P38 said, whatever you do, don't let it overheat. Fix the problem now.



Sent from my GT-P5210 using AULRO mobile app

[kapowww]

Are you sure the correct coolant is red? I thought LRs used green. Mine certainly does.

Have you checked the thermostat? A replacement could be a cheap fix if that is the problem.
As P38 said, whatever you do, don't let it overheat. Fix the problem now.


Yes it's supposed to use green but the mechanics put red in (which from here I read isn't harmful). I had a coolant leak so the tank was empty and I didn't know what was in there so ended up with a mix. The leak's been fixed by the mechanic now..

I've read much about preventing the overheating so I'm eagle-eyed while driving and seem to always watch the temp gauge.. It's probably more dangerous than texting while driving!

[FANTOM P38]

Just be cautios mixing coolants i'm sure i read somewhere that its not advisable to mix coolants as they can react to each other. I stand corrected if wrong but sure its not good!

[Keithy P38]

It depends what year the P38 is to what coolant you run.

From memory it's the green gear for gems and the red stuff for Thor. I've run red for a few years, and I haven't had major dramas, have a few leaky welch plugs at the moment, but I fear they are 15 years old so they've done their job!

Otherwise, no temp issues even idling through the bush on 40+ degree North Queensland summer days. Mine sits bang-on half way on the gauge and never strays.

Cheers
Keithy

[mtb_gary]

Mine is a '96 4.6 GEMS. I run pre mixed green and have done now for the 5 years or so that I have had the car. No cooling problems (that I am aware of :angel:). The needle doesn't move past half way and am not experiencing any coolant loss. When I hook up to the Torque app I get 85-86 C irrespective of outside temp or load. I did drain the system a few times when I had problems with the ABS modulator (I needed to remove the coolant hoses to get access) so drained and put fresh coolant in at that time, twice when the modulator failed again :(. On the first change the coolant was brownish and in need of flushing. The coolant in the expansion tank has now been a lovely bright green for a couple of years :D.

Gary

[kapowww]

Mine is actually still red and hasn't turned brown as previously thought (looking at night). I'll switch to green next time I do a full flush but should be fine for now.

Here's a pic of my temp gauge and where it stays. Not sure if I need to burp it one more time but will try when I have time.

75699

[mtb_gary]

Kapowww
I've just taken a quick pic of mine with the torque app displaying coolant temperature.

75707

It looks like your temp is fine...

Gary

[kapowww]

Thanks for that Gary, appreciate it. I'll invest in the app and adapter..