Parts - Modifications - Oil cooling
T25 diesel oil-cooling
Standard 1.6TD (JX) installation uses a 'heat-exchanger' same as the WBX petrols. This is fitted to the filter housing between it and the filter element. Piped into water coolant, so initially oil warmed quickly, subsequently oil cooled as it gets hotter than water.
Whilst this is probably just about adequate for a std. JX from new, TD diesels put a lot of heat into the oil due to the piston cooling oil-jets and the fact that these diesels put a lot of heat into the oil at higher revs and power levels. T25s are heavy and draggy so always cruise at high powe levels (relative to cars)
It is generally known that 1.6 TDs and esepcially 1.9TD conversions heat their oil a lot, and high oil temps then reduce oil pressure. 110~120C and more when hill-climbing in hot weather are quite common... 130C is considered too hot long term, even for fully synth oils. This will shorten engine life.
Thus, it is highly recommended that additional oil-cooling is fitted. The normal solution seems to be a pressed-plate oil cooler having 19 rows and full width (235mm) up-front fitted in front of the main coolant radiator usually at the bottom. This entails lomg hoses and an adapter plate for the oil filter housing.
Rear mounted coolers can be arranged to allevaite high oil temps, though it has to be well thought through to be effective enough
Mick&Tracey: Any particular oil-cooler I should look at for my ex Seat Ibiza 1.9TD?
Search eBay for MOCAL or British make (avoid grey-boxed un-named Chinese copies) - try to get new if poss. 19 row ideally, 1/2 BSP fittings prob. about best (I went mad and used 3/4"). £30 ~ £50 if lucky, they're £100 new... it's the hoses that'll cost unless you can find a tame cash source, [i]about[/i] 13.5' and 14.4' required (about!).
Adapter plate SP1 or OTSP1 from thinkautomotive as well as other suppliers (see Parts suppliers)
Rear mounted oil-coolers
Require large fan running continuously; need to ensure fan assists natural air-flow direction; yet something else to get dirt blocked on a syncro; avoids long hose runs; but long hose runs add to oil capacity, generally a good thing; unless outside engine bay adds even more heat to engine bay air, etc.