Oil temp running away on a 2.0 16v!!!

[Akinesis 0]

Was driving back to Portsmouth on Sunday when I flicked through my MFA computer. When I jumped passed the oil temp I noticed it was in the high 130's. I kept it on and saw it climb as high as 158C :shock: The hottest I've seen it was 138C when I was sat in crawling traffic for about 2 hours, and it normally runs between 98-108C.

 

I slowed right down (wasn't going fast anyway!) to about 55mph in panic, leaving plenty of gap between the car in front so the engine got plenty of air. I was starting to think head gasket, or low on oil. I was about to pull over when it slid back down to around 120C. A carried along for a while and it stayed at this temp (still a lot higher than I like!) when it suddenly jumped back up again.

 

These changes didn't seem to matter whether I was going fast, slow, up-hill or down-hill. The water temp was sat a little higher than normal, but was steady. But I thought it best to keep the speed down anyway (ended up tailing a caravan all the way :lol:)

 

When I got back I checked the oil, which was all fine (only did a change about 2k ago anyway) and there was no mayo on the rocker-cover cap. The water still looked pink and exactly on the max-mark, but I couldn't get the cap off as the water was still hot - still need to check that though. I left the car running on the spot for about 10 mins, keeping a close eye on the oil temp. It climbed to 130C (which has been normal for this car at stand-still) and didn't move from there.

 

Any idea's folks? Did a search but it wasn't fruitful. Just stuff about the temp sender, mostly (which I hope it is, rather than the head gasket or a blocked oil pick-up!). Anyone else had a problem like this, or am I going to have to embark on another journey of chasing my tail around the car?? :( I've assumed that 100C is normal running temp, 130C stand-still temp. I have seen people saying as low as 70C though, so I don't know what's right :shrug: As in title, car is a 94 2.0 16v

 

Cheers, all

[Abdul 0]

Are your fans working mate? The hottest i ever had my valver was after an 8 hour stop start stint between leicester and essex, i hit 128 degrees on my oil and that was on a humid day too!

 

Im sure your temp readings are out aswell man, i mean 158 would surely cause some long term damage, when u popped the bonnet did u feel a serious blast of hot air?

[davidwort 0]

a dodgy earth to the head can cause wild oil temp readings as the sensors rely on the earth to complete the circuit.

a 16v shouldn't run with oil above 110 degrees whether stationary or cruising really, hammer them and it will creep up but even so I'd say 120 was way high, I've had several 16v engines over 15 years and never had one that hot whether sat in traffic with outside temp over 35 degrees or flat out on the autobahn.

[Akinesis 0]

By the time I got ther car back the temp was back down, so there was no blast of heat. The fan is working, yeah. But I turned the heaters on full-blast to help get the engine cooler as I was near home.

 

I need to clean all the earths off because I have that lumpy tick-over problem. Looks like I'll be doing all the Earths. Hopefully grubbgy earths is the cause of all my problems - how nice would trhat be!! The engine bay is quite dirty so it could well the the cause.

 

Here's hoping!

[Akinesis 0]

OK, had a look the other day at the connection on the sensor and it was pretty loose! I crimped it on tight and now I get a much more responsive reading. However, the oil temp still runs high. Went up to 144C the other day, but I think this is because the fan doesn't always cut in I think I'll be wiring a switch to the fan at some point!

 

I was reading through another post that mentioned oil temperature running high when a cheaper oil is used. I'm using some stuff from GSF that cost me about £11. I did question the oil, but the guy (who I know anyway) said he uses it in his G60 and says it's fine. But when I first picked up the car the temp did sit around the 100C mark. So I'll be doing an oil changed for some of the pricey stuff next week for sure and see if this cures the problem.

 

What oil would people suggest for a valver?

[davidwort 0]

I use the cheap GSF stuff (10-40 semi synth) in my 16v, nothing wrong with it at all.

[Akinesis 0]

Then I'm stumped. Unless it's a flicked filter/pickup that's restricting the flow?? I will still change the oil and flush the coolant to see if it helps.

[skinnyman9000 0]

Christ I thort my valver ran hot at 110-118! Highest I've ever seen was 128, and a water pipe failed shortly afterwards. It's all very odd, some people rarely see over 100, whereas my valver has ran around the 110 ever since I bought it 3yrs ago.

 

I've often wondered if getting a secondary oil temp gauge is worth it, can't say I trust the mfa readings to be honest

[Jim 2]

Good luck chasing this one down. I was chasing high temperature gremlins on my 2.0 16v for ages and replaced so many things... radiator, water pump, thermostat, oil cooler, coolant (so many times) and none of them have made a jot of difference. DG Autotech had the car for a few days and spent some time with temperature probes inserted in various places in the engine bay and are convinced that the temperatures are OK and that the MFA is simply lying. Even cruising along at 60MPH the oil temperature says 116 centigrade on mine. I agree with DG's diagnosis - it's lying!

[skinnyman9000 0]

I've been driving around today and my temp wouldn't budge from 114, regardless of how I was driving.

 

I think a secondary temp gauge is in order

[Akinesis 0]

Right, I drove back to Portsmouth last night and the oil temp did it's thing again. It went up to 158C at some points, but it spiked up there from 138 within around 20 seconds. Then a short while later it crashed back down to 138C. It bounced around like this the whole time, regardless of how the car was driving. During all this, the water temp stayed at 110C (when the fan should cut in). Occasionally the water temp dropped down to around 105C, and the oil temp reflected this changed and dropped to about 116C, but only for short periods before it would jump back up again. Because of this relation between the oil and water temps, I'm not sure the MFA is lying?? Does anyone have any thoughts on this behaviour?? Even at high temps, the engine seemed happy ticking over at idle.

[davidwort 0]

do what Jim had done, get hold of a temperature probe or IR thermometer and get a reading from the end of the head where all the sensors are, I reckon you are getting false readings due to a combination of old sensors, earths and wiring to the sensors.

[Akinesis 0]

Will try this tonight :grin:

[Akinesis 0]

Right - further progress! I found out that when I have my head-lights switched on my oil and water temp run high. Turn them off and they fall back down to normal temperature. When I was running along the motorway my oil temp didn't rise above 96C, turn the lights on and it jumps up to 148C. I'm glad I've discovered the problem, but now got to run through all the wires to see where the 'leak' is :(

 

Also, in the same journey my back-box disintegrated. Pretty annoyed, because the guy I bought this system off said to me it's done about 3000 miles. Well, the mid-section didn't even fit, the mid-box had cracks in it (which I managed to get welded and they seem to be holding) and now the back-box is in two pieces. But that's another story... :bad-words: