Oil pressure problem on crossflow

[chrisc]

Hi,

I have an oil pressure problem with my 1600 crossflow. Normally on idle I get a pressure of 1.5 – 2 bar and under load 3.5 – 4 bar. However, recently the oil pressure is healthy until about 10-15 minutes into driving then I get just under 1 bar on idle and no more than 2 bar under load. I let the engine reach temperature before setting off and like I say its fine for the first 10 – 15 minutes. The temperature is about 80-85 while driving. The oil level has been checked and is fine.

Any suggestions?

[DickieB]

It could just be a faulty sensor, or even the wire that goes to the sensor that is failing.  If the wire gets too hot, then it will change resistance and hence readings on the gauge. Mind you the oil pressure wire on a XF is on the intake side so should be OK on heat - unless it is sagging and is touching the block?

[nlash]

Not wanting to state the obvious here but have you done an oil/filter change recently? A partially blocked filter will cause the drop in pressure that you are experiencing, as will diluted oil

If its due a service, then i'd do one quick and check the pressures again

[chrisc]

nlash

have you done an oil/filter change recently?

Did an oil and filter change recently so, don’t think its the filter. The bottom part of engine has been renewed: block, pistons, rings and have finished running it in.

DickieB

unless it is sagging and is touching the block

i will double check thanks.

[corsechris]

A duff filter isn't unheard of....change it again in case? Quick and cheap if nothing else.

[nlash]

have you done an oil/filter change recently?

Did an oil and filter change recently so, don’t think its the filter. The bottom part of engine has been renewed: block, pistons, rings and have finished running it in.

You'll need to do another oil change after you have finished running it in, but I guess you know that.

Have you noticed this drop in hot pressures since the bottom rebuild?

Has the crank been reground and new o/size shells fitted? I'm just a little concerned for you now you have mentioned this. You must have a hp pump fitted to obtain 4 bar when cold. You should also see this pressure when the engine is hot on fast running. Only the idle pressure would be seen to drop significantly when hot

If its not the oil filter, or the quality of oil, then i'd be worried about big end clearances or oil pump efficiency. Its unlikely that the pick up strainer is going to be blocked

[chrisc]

nlash, sorry i did the oil and filter change after running it in.

Have you noticed this drop in hot pressures since the bottom rebuild?

while running it in its been fine.  since re-build didnt have much time to do any miles so took me about 5 weeks. In this time pressure was fine. The oil pump was uprated at the same time as re-build.

Has the crank been reground and new o/size shells fitted?

to be honest i 'm not sure of this, but will find out. When i get hold of the bloke who did the work.

[Thrustyjust]

What oil did you put in?

[S8ight]

have you been using it for long or short runs ??

have known freshly ground cranks be ruined after a lot of short runs.

[chrisc]

What oil did you put in?

halfords 20-40 w

Posted on April 07 2006,18:23have you been using it for long or short runs ??

Short runs while running it in and a good long run last weekend, after which i noticed the drop in pressure.

[Thrustyjust]

Put some 20w50 Valvoline oil in it.The 40 is too thin.

[DickieB]

I agree with Valvoline Racing 20W50 as 40 is too thin. There is one new problem we have found recently racing Crossflows. Some of the original 711M blocks had the holes for the main crank bearings 15 thou bigger than all the later ones. This has caused an engine failure (twice) and (2) rebuilds before we found it out. There is no way of checking from the block number as far as we know. You just have to measure it when it is apart.  Hope it is not that and doesn't come to taking it apart.

I'd start with checking the wiring to the sensor, and then an oil filter and oil change.  Burtons do Valvoline Racing 20W50 - I think it is about £18 for 5 litres (but you can get 25 litre drums)

[7SE]

(but you can get 25 litre drums)

There speaks the voice of crossflow ownership      

[chrisc]

Many thanks for the replies. Will get started on it in the morning, as it's my main car at the moment think it will be a quick bike ride to the local motorfactor