afternoon all, it's been a while. Question to rack brains over as I am sure we are missing the obvious. The race Polo is coming out of retirement to become a track car. Originally it was the N/A 2.0Ltr engine then in a hurry we through in the 1.8t which was much better. Long story short. It always ran hot, very hot!! I was convinced we had routed a pipe wrong or something, or the flow is wrong. So I would like to see what's what with it once and for all. I will attach a drawing of what's on it in terms of coolants hoses etc and see if one of you can see something. Feel free to shout at me, ask me a question. Cheers for now Doug
What is hot, oil or coolant? What are the temperatures? What oil and coolant are you using? Do you have an oil cooler or is that the heat exchanger you've drawn as that yellow box? The setup you've drawn looks like the standard routing with the heater-radiator deleted. My engine (ABF, no turbo) was also running hot, so I changed the radiator to a 3 row aluminium from a Civic (courtesy of TonyB). I now use the Motul Mocool (similar to the red line water wetter people advised me) with demi water. I deleted the heat exchanger and added a 13-row oil cooler. Temperatures have dropped massively and I need to shield off the oil cooler to get the engine up to temperature (then remove the shield).
An oil cooler was supposed to have gone on at some point but never did. I presumed it was coolant getting hot as I had it in my head a hose was wrong so the flow was wrong or something. It has a loop (red in picture) which I was never sure about. Correct with the heater matrix delete, don't need it in the race car, hot enough. Always used VW coolant and Castrol oil, same with old engine. Would be good to know correct oil/water temp. Race technology dash just gone in, oil temp/pressure are fitted but awaiting water temp sensor to fit. But pre dash the water temp gauge would go off the scale at one point. So presumed it was a water thing. Got me thinking now.
Oil temp range is OK between 100°C to 120 °C. You can go to 140°C with high quality oil but that's only for high spec oils, and advised to change directly afterwards. I am not familiar with the Castrol line but suppose you're not running standard 10W40 in that thing. I am a big fan of Motul, been using it for 13 years now. I use the 300V Le Mans oil in 20W60 which is really high quality and am really satisfied about it. For the coolant, I never thought the addition would make so much difference but it does. I cannot pinpoint it exactly as I've made 3 changes at the same time (rad, coolant and oil cooler), but in the current, as well as in the previous 1.8PL engine, the temp meter always went to 75%. This is quite normal for a MK2, so nothing to worry specifically, but now I use the Mocool it goes to the center of the gauge and stays there- never seen before
Thanks for all the info daNpy, there are some things i need to look closer at, off the top of my head I can't remember oil details but as Castrol were a sponsor it was all their top stuff, changed frequently like the brake fluid (every race). I am on it in a minute so will have a look at bits, don't think the water sensor will arrive today but it still has the original one fitted which I can OBD into, but I remember it gets hot sitting in garage. Hence the thought of flow wrong or something, cheers again
No problems mate I am just sharing my knowledge and experiences, and I hope to learn something as well. Just try to get some temperatures out so you know what you're doing now and then try to improve. I have made quite some mods on my NA ABF and I reccon a turbo engine gets way hotter. A first try would be to get water wetter in there, I'm really curious what it really does in terms of temp drops
would still be interested in the flow side of things, is it right or like I feel, is it going against itself and not flowing correct. Had a run in garage this morning and it does get up to temp quick. I will give it another run and see what coolant temp goes to just idling.
Is the thermostat working correctly? I see now there is no front outlet like on my ABF/9A/PL engine, but that one is going to the rad and down to the pipe. There are 3 loops in my engine(s), all going from pump up through the engine and then - front output, down to the pipe, into heat exchanger, parellel into the pump - front output, into the rad, back into the pump (via thermostat) - side output, going to reservoir, heater rad, tube, return from heat exchanger, then to the pump Your engine still looks like the pump is pumping the coolant up in the engine and then returns on the outside.
Thermo seems ok, top hose warm before bottom but then both gained temp together, i let it sit and it got to 110 degrees on OBD reading off ECU and dash showed 99 oil temp before I cut fan in (which is on a switch).
Coolant temp seems a bit high but you're not driving. Oil is very oke but again, you're not driving and using the engine
