Thread: Best Tdi 300 Overheat Alarm

I have the low coolant alarm , as incisor says , you don't get much warning , it works for me .

I tend to agree with Judo here; a cylinder head temperature gauge covers not just coolant loss but any other problems leading to overheating. I've used Auberins CHT gauges (Auto gauges, EGT Boost : auberins.com, Temperature control solutions for home and industry) on both a Tdi Disco & Isuzu Defender. Work well, very responsive and relatively inexpensive. Also can switch a relay if you want to add an additional buzzer / warning lamp (say in a very noisy Isuzu powered 110!).

And they come in a range of pretty LED colours

I would highly recommend some type of alarm , who looks at the temp gauge every 3 mins .

For me the most important thing is knowing the temperature of the engine and a low coolant alarm will not tell you that. What if the thermostat was to fail and not open? The engine temperature monitor/alarm would tell you but a low coolant alarm wouldn't. A low coolant alarm would be good as a secondary alarm but I don't think it is ideal as the primary one.

Pete

Originally Posted by rick130

Hmm, there is no way on earth I'd set my engine up like that.
Too great a risk of putting yourself in a precarious position on the open road with the engine cutting out at just the wrong moment.

In the days of pre-electronic diesels, a lot of companies I drove for had those types of systems. Most common was one called (IIRC) a Kysor Alarm. Had a chrome over-ride button, had to use it a few times in a Bedford 4wd tipper that would momentarily drop oil pressure below the cutoff when it was hot. Used to do it a fair bit in stop-start traffic going through the city. Most embarrassing was the alarm buzzer, you could hear it a hundred meters away

Originally Posted by dero

I would highly recommend some type of alarm , who looks at the temp gauge every 3 mins .

Probably showing my age, but I was taught to continually scan the gauges every 30 seconds or so - been doing it for so long that I get irritated driving modern cars with nothing but idiot lights fitted

Probably showing my age, but I was taught to continually scan the gauges every 30 seconds or so - been doing it for so long that I get irritated driving modern cars with nothing but idiot lights fitted

Good practice , but probably not the norm for most of us , certainly not me .
Myself & others have suffered from the rapid overheating caused by fairly minor loss of water in a 300TDI . dodgy filler cap , leaking hose , head gasket failing ,etc have cost me dearly in the past , not any more . The low coolant alarm picks it up and warns you before it's too late . Relatively cheap insurance against a possibly quite large expense .

Originally Posted by rick130

Hmm, there is no way on earth I'd set my engine up like that.
Too great a risk of putting yourself in a precarious position on the open road with the engine cutting out at just the wrong moment.

FWIW 105° is well within operating limits of a Tdi, I've seen it multiple times with an accurate mechanical temp gauge, if you want to use some sort of alarm, set it past 115°.
IIIRC the high temp fan switch on a Disco switches at close to that temp.

I'm with you on this one Rick and not just on the open road. Imagine doing a right hand turn, oncoming traffic is heavy, you get a small gap and go and your motor cuts out.

Back on topic. I have both a low coolant alarm and a temp sensor on the head.

I used to have just the coolant alarm which I found to be not working the hard way.

Needless to say a new head came from Turners in the UK and I asked them what was exceptable temp at the head and they told me 110 was fine.

So I now have both but if I was to have just one I would use engine temp.

truedogz, welcome to the forum. You don't live far from me so we should catch up for a throffy or three one day

Originally Posted by incisor

the wifes 300tdi has the coolant alarm as i really want to know asap when there is a lack of moisture, for whatever reason....

they heat up so quickly

Dave. Are you referring to the 300tdi or the wife?