rsweeney 40 Posted July 19, 2015 Report Share Posted July 19, 2015 (edited) problem is with my 1994 golf vr6, just changed headgasket, rebuilt cylinder head and runs sweet as a nut, however oil temp and coolant temp seem to be slightly high. on a gentle drive around 35mph oil sits at 98-100, coolant 90 but creeps just shy of 100 sometimes if moving slowler.Cylinder head has been rebuilt, new shell HX7 10w40 oil and genuine VW filter, hydraulic lifters, NGK Spark plugs, lambda sensor, inlet manifold temp sensor, all gaskets etc.Runs really smooth, no leaks, but noticed there isn't masses of pressure in the cooling system ( water pump is clearly working as i can see coolant being disturbed in the header tank ) any ideas Edited July 19, 2015 by rsweeney Link to post Share on other sites
Bealieboy 1,625 Posted July 19, 2015 Report Share Posted July 19, 2015 Air lock perhaps? How about the stat? Link to post Share on other sites
rsweeney 40 Posted July 21, 2015 Author Report Share Posted July 21, 2015 thermostat is a new genuine part, its got full circulation as all the pipes are hot and i've tried bleeding the cooling system a few times but there are still small bubbles of air when you feel the upper matrix hose! trying a spare expansion cap today as i have a feeling that its not keeping system under pressure Bealieboy 1 Link to post Share on other sites
Bealieboy 1,625 Posted July 21, 2015 Report Share Posted July 21, 2015 Sometimes the seal goes on the cap but I thought you struggled to retain any coolant if that was tits up. VR6Pete 1 Link to post Share on other sites
Bealieboy 1,625 Posted July 21, 2015 Report Share Posted July 21, 2015 Maybe the rad not as efficient as it was, you could run the garden hose to try and flush it a bit. rsweeney 1 Link to post Share on other sites
daveyboy 897 Posted July 21, 2015 Report Share Posted July 21, 2015 You could have a small leak somewhere and air is being drawn in. Link to post Share on other sites
reynolds9000 26 Posted July 21, 2015 Report Share Posted July 21, 2015 fans turning on? is the drive belt between the two blades intact? Link to post Share on other sites
Mk3highline 287 Posted July 22, 2015 Report Share Posted July 22, 2015 How about the coolant temp sensor does that normally read slightly higher when on its way out??? rsweeney 1 Link to post Share on other sites
rsweeney 40 Posted July 24, 2015 Author Report Share Posted July 24, 2015 Pressure test done no leaks at 1bar, fans kick in and belt is good, when driving the temp stays down around 90, only goes above to around 95 when crawling slowish in traffic but fans pull it back to under 90.Oil is sitting around 96-98 , it's an auto so may be why it runs hotter but don't know if these temps are normal. Bealieboy 1 Link to post Share on other sites
rsweeney 40 Posted July 24, 2015 Author Report Share Posted July 24, 2015 How about the coolant temp sensor does that normally read slightly higher when on its way out???Not sure but will try the sensor out of my other vr6 which doesn't have the same issue once it comes back from the body shop Link to post Share on other sites
Bealieboy 1,625 Posted July 24, 2015 Report Share Posted July 24, 2015 Mine sits at water temp 90 constantly, it's a manual. I've seen oil temps to 100 with the hot weather we've had on a brisk 80mph run. Vr's are well known to run hot but yours doesn't seem especially so. Fans kick in ok and the cooling system isn't leaking, so that side is functioning ok. Maybe it's just an auto thing, is the gearbox included in the cooling system? Tourque converters can run rather hot I believe.Is your after run pump working? It should whir into life when you switch on the ignition and continue until a few mins after you switch off. Adjalex Brill 1 Link to post Share on other sites
Adjalex Brill 8 Posted July 25, 2015 Report Share Posted July 25, 2015 Hi its normal for this sort of weather ..mine does to ..your oil cooler should start takin it down of the 100 mark ...they are designed to run fairly hot ...88 on normal driving after 20 min drivin ..approx ..always use genuine thermostat and sensors ...tps sell them ..it makes all the difference .. Bealieboy and Adjalex Brill 2 Link to post Share on other sites
VR6Pete 1,455 Posted July 26, 2015 Report Share Posted July 26, 2015 Replace oil cooler if not done already. I did this and saw a big drop in temps rsweeney and Bealieboy 2 Link to post Share on other sites
rsweeney 40 Posted July 28, 2015 Author Report Share Posted July 28, 2015 (edited) Mine sits at water temp 90 constantly, it's a manual. I've seen oil temps to 100 with the hot weather we've had on a brisk 80mph run.Vr's are well known to run hot but yours doesn't seem especially so. Fans kick in ok and the cooling system isn't leaking, so that side is functioning ok. Maybe it's just an auto thing, is the gearbox included in the cooling system? Tourque converters can run rather hot I believe.Is your after run pump working? It should whir into life when you switch on the ignition and continue until a few mins after you switch off. aux pump is working , but yeah the auto box has an oil cooler on top which means it will be picking up heat from there as well so could be. next plan is a spare oil cooler i have for the gearbox as well as a new oil cooler for the engine Replace oil cooler if not done already. I did this and saw a big drop in temps Thanks mate sounds promising i will give this a go as i havent changed this as yet, does it matter which one you go for as there are two types? Edited July 28, 2015 by rsweeney Link to post Share on other sites
VR6Pete 1,455 Posted July 28, 2015 Report Share Posted July 28, 2015 There's only one engine oil cooler type AFAIK. I got a febi item from AVS. Carful of the hose from the crack pipe as you remove though. Bealieboy 1 Link to post Share on other sites
rsweeney 40 Posted July 28, 2015 Author Report Share Posted July 28, 2015 ok cheers just thought the early ones had metal caps and the later type where metal ? Link to post Share on other sites
reynolds9000 26 Posted July 28, 2015 Report Share Posted July 28, 2015 the engine cooler itself is the same, the cap is interchangeable metal for plastic, vise versa. Link to post Share on other sites
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