what colour oil pressure switch should I have?

[Gary.pb]

I recently bought a recon engine for my van. After a Couple of minor teething problems the engine was running perfect. However yesterday my buzzer of doom came on. I pulled over immediately and the oil level was fine I started the engine again started driving and it happened again. At this point I didn't want to risk it so I got recovered home. It seemed to happen when the engine got warm at about 2000 rpm. It wouldn't buzz beforehand. I will obviously get the oil pressure checked before I use it again. However I'm convinced it's more likely an electrical issue. When I changed my oil pressure switch I remember there were lots of different coloured ones. I left mine in my exchange engine as was going to fit a new one so I just want to make sure I've fitted the right one. Mine is a 1.9dg which is completely standard with the exception of a stainless exhaust. I think from memory I fitted the black one

[T3luestar]

Loads of info here.... https://www.brickwerks.co.uk/brickwerks ... -switches/" onclick="window.open(this.href);return false;

My buzzer went off due to a corroded plug and broken wire. Always best to get it checked out though.

[Gary.pb]

Loads of info here.... https://www.brickwerks.co.uk/brickwerks ... -switches/" onclick="window.open(this.href);return false;

My buzzer went off due to a corroded plug and broken wire. Always best to get it checked out though.

That's exactly what I needed..

Thanks for the link

[henryb]

Hi Gary, we need to change the oil pressure switches on our 1.9dg (1989) T25, we think one of them is the blue switch but not sure on the other as three choices white, grey and black, had a look at the Brickwerks link but it seems 88 onwards there is a choic of switches? Also how easy are they to replace seems they are in really awkward positions, cheers

[Simon Baxter]

Easy way is just to fit the lower pressure one.

[itchyfeet]

Hi Gary, we need to change the oil pressure switches on our 1.9dg (1989) T25, we think one of them is the blue switch but not sure on the other as three choices white, grey and black, had a look at the Brickwerks link but it seems 88 onwards there is a choic of switches? Also how easy are they to replace seems they are in really awkward positions, cheers

Yes as Mr B says fit the grey switch in the high pressure location under waterpump ( the lowest of the options) , a blue is fitted between push rod tubes.

Why do you feel the need to change them, whats wrong?

[henryb]

Hi itchyfeet, thanks for your reply, we got the dreaded buzzer of doom and flashing light oil, got oil pressure checked and thats fine, changed oil and filter still doing it, so thought next on list switches,its always been fine never had a problem until mechanic did water jacket seal and replaced cylinder heads, and one day after getting it back it did this. It only happens when engine warmed up and been driving for say 2/3 miles and sometimes goes off round corners or changing gear, its running fine and not noisy

[henryb]

Thanks simon baxter too,

[itchyfeet]

before changing switch check ( or preferably replace) the wire and connections to the high pressure switch under waterpump.
Mine had a broken wire over engine, checked OK with a multimeter but when runing it intermittantly went open circuit.

The buzzer will sound only above 2000rpm and only if the wire is not grounded by the switch, if the connection is loose it will sound but the connection must break for a second or two to trigger it.

[silverbullet]

Sounds like a bad earth return to me.
One switch is make, one is break at the rated pressure.
Check the condition of the brown wire(s) that connect to the switches. The branch that connects to the switch between the pushrods can get trapped or melted by exhaust heat from #3 and then short to earth via the engine casing.
Check the terminals in the handed white plug (green stripe) that lays on top of the engine, near the distributor and left side of the inlet manifold. The crimps on the connectors can go green, causing high resistance and triggering the buzzer.
Check the condition of the engine and transmission nose earth straps too.

[ghost123uk]

and sometimes goes off round corners or changing gear,

This is symptomatic of a loose wire or connector, likely on the high pressure switch.

[henryb]

Wow thanks for all the info itchyfeet, silver bullet and ghost123uk, will check all of that out, will be great if it that and not have to replace switches as they look awkward positions to replace, will let you know how it goes, thanks again

[Dantes]

I had this exact problem, and I had initially assumed that as the oil warmed it got thinner and for that I was loosing pressure. Kept an eye on it with a Pressure Gauge to see when it was happening.

In the end I changed my oil pump, even though the old one still seemed perfect, and fixed the issue. Easy enough job to do as long as you have good Allen key extensions (I planned to change my gasket, had a spare ready to put on, but the old one was in such a good state that it sealed again perfectly (probably the amateur in me )).

[lodgey62]

My 1.9 DG did the same,l replaced the oil,nothing, replaced both switches,nothing, turned out to be just as Itchy said,a broken wire to the switch behind the water pump,what a relief!
Hope your fix is as easy.

[henryb]

Thanks Dantes and lodgey 62, got switches and someone looking at it on Teusday morning fo fingers crossed will be sorted