oil pressure and water temp

[nordin450]

I'm a bit worried about the behaviour of my Chim in regard to oil pressure and water temp...

Just cold started and idle; Water temp low, oil pressure about 30psi
Warm and driving on highway (~70mph); Water temp about 70, oil pressure about 30psi

Believe the above is normal, here's my worry...

When warm(hot) on tickover; Water temp up to 98 , oil pressure 0-5psi

Oil pressure is kept 15psi below normal all-around

Have checked oil levels and removed air locks from coolant.
Both fans kick in from about 90 but doesn't seem to be able to keep the temp down..

Any ideas?

>> Edited to better describe the issue

>> Edited by nordin450 on Sunday 12th February 16:26

[number 7]

nordin450 said:

I'm a bit worried about the behaviour of my Chim in regard to oil pressure and water temp... Just cold started and idle; Water temp low, oil pressure about 30 Warm and driving on highway (~70mph); Water temp about 70, oil pressure about 30 Believe the above is normal, here's my worry... In heavy traffic traffic; Water temp up to 98 , oil pressure 0-5, the oil pressure does increase as soon at I'm driving again It's cold outside at the moment and the bible recommend a max water temp at 95c on a hot summer day... Have checked oil levels and removed air locks from coolant. The fan does kick from about 90 but doesn't seem to be able to keep the temp down to 90.. Any ideas? >> Edited by nordin450 on Saturday 11th February 20:40 >> Edited by nordin450 on Sunday 12th February 12:28

Those oil pressures do seem a bit low - I'm assuming this is a pre-serp. engine, in which case you would expect c. 20 psi at hot idle and c. 40 psi hot over about 2500rpm. Normally you'd get a much higher pressure when cold - say plus 10-20 psi - than when hot. Does the oil warning light work, and come on at all during normal driving? Different oils can have an effect on pressure - thin oils don't work well in the RV8. Idle speed makes a difference as well - should be around 900 - 1000 rpm. I'd start checking the connections to the pressure sender, and maybe replace the unit before driving anywhere.

7.

[nordin450]

number 7 said:

Those oil pressures do seem a bit low - I'm assuming this is a pre-serp. engine, in which case you would expect c. 20 psi at hot idle and c. 40 psi hot over about 2500rpm. Normally you'd get a much higher pressure when cold - say plus 10-20 psi - than when hot. Does the oil warning light work, and come on at all during normal driving? Different oils can have an effect on pressure - thin oils don't work well in the RV8. Idle speed makes a difference as well - should be around 900 - 1000 rpm. I'd start checking the connections to the pressure sender, and maybe replace the unit before driving anywhere. 7.

Manufactured -98, so believe it's a serp and not a pre-serp (have expansion tank which is fitted front right).. The Oil in there at the moment is Mobil1 15w50 fully synthetic. Idle is between 900 and 1000.
Will search in the bible for how to check the pressure sender.
Any ideas about the coolant temperature?

[mongoose]

Your oil pressure does seem to be under-reading by about 15ish psi all round.The serp engines sit around the 45psi mark when on the run(3k revs plus)when hot,and will be around this when cold even at lower revs.This is due to the constant volume type pump.This could just be a sender fault,but it could also indicate worn bearings in the bottom end(i had this on my first chim).Does the engine sound a bit 'knocky' at the bottom on hot tickover?.I'd still try a new sender first mind you,as you've little to lose there.Your temp sounds fine when on the run,70oC at this time of the year is a normal figure to see on the gauge,even though the real temp is actually higher(windchill on the sender).From the three i've had,if you find the fans keep the temp down in traffic to between 90-95oC,for as long as you like,then all is well.Edited to add,that it's always worth checking that both fans are working though.

>> Edited by mongoose on Sunday 12th February 13:53

[nordin450]

I agree with the observation that the oil pressure is 15psi below normal all time around. There is no 'knocky' or abnormal noise on hot tickover..

What's the function of the Oil sender?

Could the low oil pressure possibly be the cause for high temp (~98c) in heavy traffic?

Confirmed both fans working.


>> Edited by nordin450 on Sunday 12th February 16:18

[mongoose]

nordin450 said:

I agree with the observation that the oil pressure is 15psi below normal all time around. There is no 'knocky' or abnormal noise on hot tickover.. What's the function of the Oil sender? Could the low oil pressure possibly be the cause for high temp (~98c) in heavy traffic? Confirmed both fans working.

I cant see the oil pressure being the cause of the high temp.I don't think,from what you describe,that the temp is getting too high.If i doesn't go higher than 98,and if you stood still,it dropped to 90-95 eventually and stayed there,then nothing sounds wrong to me,from what i've experienced,don't let it make you paranoid.
The function of the oil pressure sender is to convert the pressure into a signal for the gauge.I'd just change it,if ever it's suspect(simple job and not too expensive),then it's one less thing to worry about.

[nordin450]

mongoose said:

I cant see the oil pressure being the cause of the high temp.I don't think,from what you describe,that the temp is getting too high.If i doesn't go higher than 98,and if you stood still,it dropped to 90-95 eventually and stayed there,then nothing sounds wrong to me,from what i've experienced,don't let it make you paranoid. The function of the oil pressure sender is to convert the pressure into a signal for the gauge.I'd just change it,if ever it's suspect(simple job and not too expensive),then it's one less thing to worry about.

Once the temp is up to 98 it doesn't drop until I'm cruising on the highway. Reason for being worried is mainly because it's really cold now, on a hot day I suspect the car would overheat Maybe i'll just have to deal with it when that day comes

Based on your advice I'll get the Oil pressure sender replaced.

[dlewis]

John

Thermostats usually fail shut, so temps could rise and oil thin.

Worth checking?

Dave

[toon tvr]

Sorry for jumping onto your thread but this thing about oil pressure, mines reading 30 psi at idle and hovers just below 60 psi at 3k + revs.

Am I lucky?
Duff switch or gauge?
hidden problems?

John

[nordin450]

dlewis said:

Thermostats usually fail shut, so temps could rise and oil thin.

Don't fully understand what you mean by "Thermostats usually fail shut"....

[toon tvr]

nordin450 said:

dlewis said: Thermostats usually fail shut, so temps could rise and oil thin. Don't fully understand what you mean by "Thermostats usually fail shut"....

The thermostat contains a little cylinder with wax in it at low temp the wax is solid as the temp rises 82degrees the wax melts and expands pushing open a piston and allowing water to flow around the cooling system via rad for cooling.

You can check a thermostats operation simply by dropping it into a pan of boiling water(on a string)

[number 7]

I thought 'stats usually failed open, so you end up with an overcooled engine.

7.

[GreenV8S]

The most common failure leaves them half open, so you get too much cooling in winter and not enough in summer.

[Ozstyle]

I had a duff oil pressure sensor on my serpentine Griffith. At idle (hot) about 5-10 psi, on the run about 15 - 20 psi regardless of revs. New sensor at idle(hot)just under 30 psi, on the run above 2000 revs just under 60 psi.

Ozstyle

[andy-w]

For the price it costs for a stat and the fact that you are going to take it out and test the old one anyway you might as well just get a new one...they cost under £10. If you take yours out and it is NG then you need to get a new one anyway!!!