2.5 DT: Lazy Temperature Gauge and Topping Up Coolant

[Kernowel]

Hi all

97 2.5 Diesel. Two related questions:

1. My temperature gauge has started barely working. It climbs from below the baseline marker to just about on it - so barely a couple of mm. The engine and rad etc, was replaced 6 months ago in Oct-24 by a Bongo specialist, and it has been finding 1100 on the temp gauge very quickly, until a couple of days ago when it started doing this. Any ideas??

2. So I checked the coolant before I set off yesterday and it was low. Do I need to bleed the system just to top it up or can I pour half a pint straight in the expansion tank when the system is cold?

Much appreciated
H

[gilly99]

Don't drive it!! Sounds like an airlock - you urgently need to bleed the system,.... and find why the coolant level has dropped. Likely nothing wrong with the temp. guage, but they are notoriously inaccurate and laggy. Get a low coolant alarm fitted!!!!

[Bongolian]

Defo bleed the system.
Mine had a temp gauge that looked okay ticking over, but was quickly going off the scale as soon as it was driven. The header tank was topped up but still the same, so I clearly had an air lock in the system.
It’s not a difficult job as I found out bleeding mine for the first time recently.
Search this forum or the tinterweb and you’ll find plenty of videos to help, get a funnel and some coolant, and a willing helper you’ll be sorted.

[BromGo]

Is it normal for the gauge to be lazy for quite a while after starting the engine? Like a minute or so?

[g8dhe]

The gauge isn't lazy, it just takes time for the engine to heat up the coolant and hence display on the gauge.

[Hazzobongo]

I'll drive two miles from starting the engine before my gauge moves over Winter and Spring, Summer is around half that distance, 2.5 diesel, I also try to drive gently till the motor hits the 11 oclock mark to reduce wear and tear. H

[haydn callow]

When you have sorted out the issues, consider fitting am Low Coolant Alarm….Haydn Alarms. Have a Bongo specific alarm developed years ago with the help of this web site/ club.