nickwilliams Posted January 13, 2012 Share Posted January 13, 2012 This weekend's project (among others) is to fit an oil pressure gauge to the 300TDi engine in my 90. No bother there - putting it alongside the oil pressure switch obviously makes sense. However, I've also got an oil temperature gauge to fit and since I'm going to have to fabricate the parts to fit the sensor on the engine anyway, I'm wondering if simply sticking it alongside the pressure switch and pressure sensor is the best thing to do. Apart from the fact that it will potentially be vulnerable to damage since it's another lump sticking out above the oil filter, it also occurred to me that having it stuck out in some pipework, waving about in the breeze, it might not actually give a very good measure of the temperature of the oil. It would be easy enough to make a fitting to put it in the inlet (or indeed, the outlet) side of the oil cooler, or it could even be put in the sump pan. Maybe the best thing to do is to forget about the engine oil and measure the gearbox oil temperature. I could get a second gauge and measure the transfer box temperature as well, but now we're getting carried away. So, what do people think about the best place to measure the oil temperature? It's not only got to give a meaningful readout of temperature, but it's also got to be fairly easy to get to, both for fitting the sensor and for the wiring, and it's got to be reasonably well protected against mechanical damage. What do you reckon? Nick. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted January 13, 2012 Share Posted January 13, 2012 On the 200 TDi the filter housing has a bung for doing just this... 300 Might be the same. Pressure gauges just Tee into the warning light sender. Now, why 2 gauges for 2 temps when you could just run the sender wires in to an ON - ON switch and then out to the gauge, switch 1 way and theres engine oil temp, switch the other and yep, theres your transfer box temp. Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted January 14, 2012 Share Posted January 14, 2012 Now, why 2 gauges for 2 temps when you could just run the sender wires in to an ON - ON switch and then out to the gauge, switch 1 way and theres engine oil temp, switch the other and yep, theres your transfer box temp. because sods law dictates you can guarantee the one will be melting while the gauge is showing the temperature of the other one! Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted January 14, 2012 Share Posted January 14, 2012 because sods law dictates you can guarantee the one will be melting while the gauge is showing the temperature of the other one! I reckon you'd probably smell that! Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted January 14, 2012 Share Posted January 14, 2012 reckon you are right there Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 14, 2012 Share Posted January 14, 2012 If you 'T' it in (done it meself before now) you read a conducted temperature rather than an imersed temperature, which can be much lower. I learnt this when I started testing heat exchangers for a living. I'm starting to think the best place to measure oil temp is just before the oil enters the engine. That's the temperature the bearings will see. (with a bit of heating or cooling from the block maybe)? Quote Link to comment Share on other sites More sharing options...
agent nomad Posted January 14, 2012 Share Posted January 14, 2012 How about the sump Drill and tap the sump plug for the temp sensor this measures the temp after the heating effect of the engine using the oil, this is where it was fitted to my Westfield sports car with a wet sump, it was in the bottom of the dry sump system oil tank when I had a dry sumpped engine. Its all relevent as you need to know where it it measured and set a datum or normal temp and ack upon step changes. Paul. Quote Link to comment Share on other sites More sharing options...
Paul Woodward Posted January 14, 2012 Share Posted January 14, 2012 I've fitted mine in the sump. I brazed a boss into the rear face of the sump just above and to one side of the drain plug. The sump is double skinned so I made the boss with a flange and fitted from the inside and brazed it inside and out. The truck isn't on the road yet so no idea if it's going to work! Quote Link to comment Share on other sites More sharing options...
gilloverland Posted January 14, 2012 Share Posted January 14, 2012 Simple answer is the sump because you want to know the bulk temp of the oil. Quote Link to comment Share on other sites More sharing options...
Michele Posted January 14, 2012 Share Posted January 14, 2012 I too have temperature and pressure gauges to fit. I would avoid the pan as it's too exposed. The two (bolt-on) choices I have found are this which goes between the oil filter and its support (so the filter would also sit lower, hopefully without banging against the axle), and has 4 ports; and this which goes in the stock location. Available from Madman, SA...might take a while to get hold of...uh... I'd like to fit everything in the stock location but I didn't find anything good. Quote Link to comment Share on other sites More sharing options...
Michele Posted January 14, 2012 Share Posted January 14, 2012 Link to the Madman tee: http://landyonline.co.za/shop/product_info.php/cPath/23_46/products_id/49 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 15, 2012 Share Posted January 15, 2012 Simple answer is the sump because you want to know the bulk temp of the oil. Exactly! Quote Link to comment Share on other sites More sharing options...
Gremlin Posted January 15, 2012 Share Posted January 15, 2012 Mine is plumbed in one of the oil cooler lines at the rad. G Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted January 15, 2012 Share Posted January 15, 2012 IIRC the military landrovers had it plumbed in to the line leading to the top of the oil cooler, which itself was fed from a sandwich plate between the oil filter and housing. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 15, 2012 Share Posted January 15, 2012 S3 FFR trucks had it in the sump, as in my lightweight. Quote Link to comment Share on other sites More sharing options...
nickwilliams Posted January 15, 2012 Author Share Posted January 15, 2012 In the end what I have done is to drill a hole into the gallery in the top of the oil filter assembly and threaded it so the body of the temperature probe is in the oil flow. It seems to work but I am surprised by how slowly the oil temperature rises, and how cool it stays (although admittedly it was about -3 deg. C when I took it for a test drive last night). I'd expected the oil temperature to rise more quickly than the water (which is slow enough as it is!) but in fact the oil takes about 10 minutes of steady driving before it starts to register on the gauge. With steady driving it seems to level out at about 70 deg after maybe 20 mins but it got up to about 90 when towing a (fairly lightly loaded) trailer up a hill over towards Glossop earlier this morning. Does this sound right? Nick Quote Link to comment Share on other sites More sharing options...
western Posted January 15, 2012 Share Posted January 15, 2012 on my 200tdi the oil temp sensor is item PRC4372 on my modified parts page atteched below, it sit in the oil flow at the filter head, & reads fine, normal operating temp is around 74 degrees & that is stamped on the oil cooler thermostat which is item 2. oil pressure gauge trnamitter fittings.pdf Quote Link to comment Share on other sites More sharing options...
nickwilliams Posted January 15, 2012 Author Share Posted January 15, 2012 Thanks Western. It looks like I got the sensor in the right place and it's reading correctly then. Nick. Quote Link to comment Share on other sites More sharing options...
integerspin Posted January 16, 2012 Share Posted January 16, 2012 Does this sound right? Nick That sounds about right. But it's years since I had an oil temp gauge. I have a montego oil cooler[water cooled] so the oil probably warms up much quicker. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted January 17, 2012 Share Posted January 17, 2012 Sounds fair to me too. And my dry sump looks to be worse still as there is twice the oil. The thermostat is open and the tank is still cold. With the water jaket'd around the really hot bits I suppose it will get hotter first? Which is a good argument for a water cooled oil cooler Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 17, 2012 Share Posted January 17, 2012 Which is a good argument for a water cooled oil cooler Definitely, oil needs to be at a good temperature to lubricate properly, it's one of the reasons why short journeys are bad for vehicles. Later RRCs had a water->oil cooler in the RH side of the rad, seemed to work pretty well Quote Link to comment Share on other sites More sharing options...
Roverbo Posted January 18, 2012 Share Posted January 18, 2012 Yep, the combined cooler is brilliant - untill the moment where the transmission oil pipe is corroded by the water, and you start to loose water in mysterious ways...then you discover that your atf oil is like strawberry milkshake, and the gearbox starts to act strange. Seems like I´ve saved the box with several oilchanges - it acts almost normal now. But I will never buy a secondhand combined radiator again. Quote Link to comment Share on other sites More sharing options...
Howitzer Posted January 20, 2012 Share Posted January 20, 2012 The screw on type which fits between the oil filter and housing are fantastic. We called them Modene coolers at work and you could get different thickness ones. They had them on some Peugeots and Montegos etc. Dave! Quote Link to comment Share on other sites More sharing options...
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