Oil temp sensor help

Post by **Carl** » 29 Jul 2006 09:38 am

I tried fitting my oil temp sensor to my car this week - unfortunately it didn't fit - the thread was slightly too big

I believe the sensor was used on some variety of 240 before I got it - with this in mind does anyone (mac?) know what the thread size would be? My new plan is to drill it into the side of the sump, so it's out of the way.

Cheers

Carl

Website · Post by **antiekeradio** » 29 Jul 2006 10:09 am

define "my car" [engine type] = ??

Website · Post by **antiekeradio** » 29 Jul 2006 10:10 am

sump plug, isn't that M18 x 1.5 ??

Post by **mac** » 29 Jul 2006 10:57 am

Mornin' Carl,

This ? came up before I recall. As far as I know all 'redblock' sump plug threads were M18x1.5. At least the temp sensor that SteveP had off me (which was a 200 series kit) was - I put a thread gauge on it to check at the time. I have always assumed the 360 sump plug was the same as the 'tin' sump. (at least threadwise - I know it's insquare).

The nearest imperial size to M18x1.5 is 3/4"x16tpi UNF (an exact metric equivalent would be M19.05x15.875) - as near as damn'it the same thread pitch but just a little larger. It looks as though 'your' sensor is Imperial thread (which VDO certainly supply). This would certainly explain why you found it was 'slightly too big'.

If the thread in the sump were UNF and you sensor was metric you would find it too small.

The other possibility is that the sensor you have is UNF because 240s were UNF! - That would mean the sensor SteveP had from me was also UNF and he would have been unable to fit it (Steve - did it fit ?????). It would also mean that the last 940s were also UNF (which I doubt). The same sump plug (948187) has been used on 'tin' sump redblocks since the B20. It would also mean I measured the sensor I had incorrectly, and thats quite possible of course!. (I'm pretty sure it was M18 - I used not only a pitch gauge but ran an M18 die onto it as well).

Dive in anyone - this must have been seen before!!

Mac.

Post by **SteveP** » 29 Jul 2006 11:33 am

I haven't fitted the kit yet, as I haven't got a gauge panel - so I'm waiting til the next oil change, hopefully I'll have the gauge panel by then.

Post by **Carl** » 29 Jul 2006 06:38 pm

Evening Mac

Thanks for the reply. It did come up before. The part number on mine is 801/4/41 which I thought (IIRC) was the same as the one you sold to Steve so I was hoping mine would fit too. But it definately doesnt fit in the sump. I've even got a M18x1.5 boss (that I was going to use with it to mount it at the back of the sump) and it doesnt screw into that either.

Hmmmmmmmmm, I'm confuzzled.

What do you mean by tin sump Mac? The B230 I have in the garage has a tin sump in my eyes, but my 360 doesnt, it's completely different. I should take the sump plug out of that to check the size of that I suppose.

Post by **Tero Huikko** » 29 Jul 2006 08:00 pm

Just encountered the same prob installing my vdo set.

The vdo sump plug doesn't fit.
I bought a t-piece with M14/1.5 and NPT threads and now I have temp sensor by the alternator on the same place with oil pressure sender.

Works fine.

As temp sensor I used some water temp sender I found with M14/1.5mm threads.

Works fine and it's on much better location. No need to run wires under the engine. No need to remove the sensor when changing oil.

Post by **mac** » 29 Jul 2006 08:05 pm

You're confuzzled Carl - so am I now !!

By tin sump I simply mean the steel sump on 200s. 700s & 900s as opposed to the alloy finned affair on 360s.

If you have a known M18x1.5 boss and it wont fit that then it looks very much like your sensor is Imperial (almost certainly 3/4"x16). It makes me worried now about the kit I sold Steve - if that's 3/4 as well - ooer - but I measured it and I can't be that out, can I ?? - it also means I used a 3/4 die as well - humm, too many senior saga moments for my liking.

Steve - if you're reading this - we really have got to confirm exactly what thread the sensor in 'your' kit is (we know the kit is definitly a 200 series accessory). It all hinges on whether the 2/7/9 sumps have the same drain plug thread as the 300. (I've got to visit the stealers soon so I think I shall get one plug of each type to compare).

All repeat after me 'we will get to the bottom of this'

Mac.

Post by **Carl** » 29 Jul 2006 08:42 pm

'we will get to the bottom of this'
'we will get to the bottom of this'
'we will get to the bottom of this'
'we will get to the bottom of this'
'we will get to the bottom of this'
'we will get to the bottom of this'

That's what I thought you meant re the tin sump. If I can manage to shift the B230 engine (from a 940) into a position where I can remove sump plug tmrw I will compare the sizes.

As for using a water temp sensor I never thought of that. I suppose they're the same as oil temp sensors. Might try to get hold of one and give it a go. Is there not a problem with different sensors not matching the guage and giving false readings though?

Post by **SteveP** » 29 Jul 2006 09:02 pm

I am reading this in interest - theres a heck of a lot of confusion over this, and always has been since I've been here anyway!

Can I help with providing any information? I certainly don't have anything to measure threads and that like

Post by **foggyjames** » 30 Jul 2006 01:23 am

The resistance range is usually consistant between VDO temp gauges - 10-180 ohm.

I'd say it's much more likely that the 300 series one if different compared to say 200 vs 7/900, since it has the different design of sump. Random factoid: the 360 sump actually holds more oil than for the 'big' cars.

cheers

James

Post by **Carl** » 30 Jul 2006 10:49 am

Hmmm, well there's Saab oil temp sensors that have been going on ebay for ages which are M14x1.5 so might try one of those. Cant believe that didnt twig that earlier!

What are peoples thoughts about having a t-piece with a pressure and temp sensor connected out the side of the block? My concern is that it might be a bit too much weight for the thread. Might try and mount the sensors remotely to inner wing or summat.

Website · Post by **antiekeradio** » 30 Jul 2006 11:19 am

my concern might be that you are not actually measuring the oil temperature!!

there is 0,0 flow at that point. you will measure outer block temperature, with some outside air influence (large influence when wet) and only a tiny bit of influence by the oil temperature in de main oil duct.

you would better stick the sensor to the outside of your oil filter with some insulation around it.

the best way would be to take a special temp sensor (with very long tip) and mount a bung for it in the side of the oil sump, so that the tip of the sensor would be right in the middle of the sump oil.

alternatively, (warning; bodge-tastic hints are given hereafter) you could search for a miniature sensor with the same resistance values and connect it to a piece of a two-string wire and let that drop down into the sump through one of the oil return channels under the valve cover. bring out the wire trough ventilation tubes. thats perhaps the most pure way of measuring oil temp but bound to be unreliable ofcourse

Post by **foggyjames** » 30 Jul 2006 12:44 pm

I'd go for 'sender in side of sump'. I'm also concerned about the unit mis-reading when in the side of the block, although it is tapped directly off the main oil gallery. There are various other places you can get external pressurised oil take-offs, including the oil pressure test point on the front of the block, and one on the head somewhere...but I think the sump is probably best.

cheers

James

Post by **Carl** » 30 Jul 2006 01:45 pm

Hmmmm, a lot to think about.

Any idea were you could buy a bung to put into the sump? I thought I had one sorted if it was M18x1.5 as its the same size as lambda sensors and there's plenty of bungs for them to put into exhaust pipes, but that's obviously not gonna work unless I can find an M18x1.5 sensor. Or an adaptor for the imperial sensor I seem to have I suppose.