Oil pressure switch - 3200GT

A

Arvid

Member
Messages
158
Hi all,

I am a new member on this forum and I'm searching information on the oil pressure switch. If anyone has fiddled with this job,please share Your info :)

Mine is not working properly,just as they always end up. Can someone tell me if it's a 5bar or 10bar sender ? I know the instrument read 5bar but often the sender unit has capacity to read higher pressure. I can use many alternative senders,certainly of better quality,if I can establish what kind of sender unit this is. The stampings on the sender does not lead to any good information. All I think I know so far is it's a Jaeger (?),threads M14x1,5,10 ohm at atmospheric pressure and 180 ohm on full.

So does anyone know if it's a 5bar or a 10bar unit ?

As a sidenote,my car is a -99 Quattroporte 3.2 Evo. I thought I'd write my questions in this section as I suspect there are far more 3200GT than QP 3.2 owners on this forum. If it's a problem,please move the thread to correct section.

Greetings from Norway,
Arvid
 
jluis

jluis

Member
Messages
1,703
Hi Arvid and welcome to the forum.
I think no one has yet established an alternative part for the oil sender.
If you have access to one that is known to be working and can verify the resistance at various pressure levels, it will be easy to find a better and cheaper replacement.
 
A

Arvid

Member
Messages
158
Hi Jorge,

I think it should be a fair chance to use other and better senders if we could find out what the original one is. Sadly,I only have access to the one installed in the car. It could be taken out and inspected/tested but that would leave me stranded for a while.

I have received pictures from a fellow forum member with the original part number - 12v 11M7 401 981 01 8B. I suspect that the "8B" means it's a 8bar sender which could be plausible as the gauge reads 5bar. Combining that with the other info there is several senders that would fit.

One other puzzle is why the original sender only has one wire connector when the instrument has two functions - both pressure reading and warning light.

Arvid
 
allandwf

allandwf

Member
Messages
10,994
Hi, yes I have fiddled. It has Jaegar internals, electro mechanical. The contacts inside are an interference connection solely relying on a metal spring to make the contacts. When you see inside you will be amazed they even work for so long as they do. This is the main cause of the erratic and bouncing readings. The track can also wear. I am not sure what the pressure range is yet, as I am not sure the input voltage range is. I have one apart in the garage as I was trying also to source an equivalent.
 
jluis

jluis

Member
Messages
1,703
The warning light function is triggered by the cluster/gauge when the reading is bellow a pre determined value.
That's why it only needs 1 wire (plus ground) to work
 
allandwf

allandwf

Member
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10,994
jluis said:
Are you sure? That would make it an inteligent design and we know how unlikely that is :)
Click to expand...
Positive. For numbers sake, 2Bar will not bring up alarm at tick over but will at say 4000rpm. I tested it on mine when I had it. It is intelligent.
 
A

Arvid

Member
Messages
158
This was both good and bad info :) The bad part beeing that I most likely won't be able to replace it with something other than an original. Finding a switch that has all these functions would be next to impossible. I like to fiddle but this was a bit fiddly...

Would be interesting though to buy a cheap 5 or 8bar switch with the correct ohm. I reckon it would work but only as a pressure reading and not with the oil light.
 
allandwf

allandwf

Member
Messages
10,994
Oil warning light must be from ecu, as sender is basic. I am at work for another two weeks, but once back, I can easily check the pressure range of the variable resister part of the sender, but we still need to know if it uses the whole range. I will check reistance at zero and maximum.
 
A

Arvid

Member
Messages
158
allandwf said:
Oil warning light must be from ecu, as sender is basic. I am at work for another two weeks, but once back, I can easily check the pressure range of the variable resister part of the sender, but we still need to know if it uses the whole range. I will check reistance at zero and maximum.
Click to expand...

That would be great. I'm sure it's either 8 or 10 bar and I've read they are 10-180 ohm. That should be something to work with :)
 
Moz1000

Moz1000

Member
Messages
821
I have just had my 3200 oil sender changed for a new one (this is the third time in 6 months). I have the old unit in my hands and I requested to keep it for the purpose of someone with the knowledge to dissect it and assess whether there was a compatible part out there that was more reliable.

I would like to send it to someone for this purpose. Who?

Dave
 
jluis

jluis

Member
Messages
1,703
Moz1000 said:
I have just had my 3200 oil sender changed for a new one (this is the third time in 6 months). I have the old unit in my hands and I requested to keep it for the purpose of someone with the knowledge to dissect it and assess whether there was a compatible part out there that was more reliable.

I would like to send it to someone for this purpose. Who?

Dave
Click to expand...

Third time in 6 months? What are the symptoms ?
They are crapy but should last longer
 
mjheathcote

mjheathcote

Centenary Club
Messages
9,038
Is it an unusual thread? can't imagine so.
I guess it is then just a case of finding one with the same resistance values, or if not, a resistance circuit to adopt accordingly.
 
Zep

Zep

Moderator
Messages
9,270
I'm making an adapter to fit a standard oil pressure sender to a 4200/GS, should be complete in a week. Happy to do the same for a 3200 if I can get an old one. The information is usually stamped on the flats of the base, maybe post some pics?
 
allandwf

allandwf

Member
Messages
10,994
This is all in hand it's 14mm can't remember the pitch, possibly 1.25, jaeger internals, I'm measuring resistance values once I get home, mine is in bits on the bench. Just need to confirm range in bar.
 
Zep

Zep

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9,270
allandwf said:
This is all in hand it's 14mm can't remember the pitch, possibly 1.25, jaeger internals, I'm measuring resistance values once I get home, mine is in bits on the bench. Just need to confirm range in bar.
Click to expand...

Fair enough. I imagine the range will be stamped somewhere. In the course of my research I have concluded that practically all single wire automotive transducers are 0-180 ohm across the given range. I have a 0-5 bar 1/8 NPT (taper) going spare if it's any use. Due to the supplier shipping the wrong one and not wanting it back
 
allandwf

allandwf

Member
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10,994
Everything but the range seemed to be stamped on it. I will post as many details as I have once I get back,(18th.) There did not seem to be a straightforward equivalent though.
 
Fat Arnie

Fat Arnie

New Member
Messages
428
If its any consolation the VDO ones are rubbish. I suspect the OEM ones come from VDO - the F355 ones are VDO. Search the VDO catalogue and you will find the one with the correct thread M14 x 1.25 sounds right for a European engine. 180 ohms is the norm. What they respond badly to is vibration - get some one to make up a braided hose so you can mount it remotely.
 
allandwf

allandwf

Member
Messages
10,994
If we can find a way of opening them neatly, but more awkward, sealing them again, then just soldering the pin Connections and not relying on an interference connection would work wonders.
 
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