Mercruiser Water Temp Sensor 87-814079

[Converging]

http://www.ybw.com/forums/attachment.php?attachmentid=13564&d=1315752987

I have been trying to locate this water temperature sender - Mercruiser reference 87-814079. It is fitted onto my 3.6D cylinder head

It appears it is now no longer available with no obvious replacement. To make matters worse it also controls the glow plugs making an automotive replacement difficult.

Has anyone had to replace/worlk around this problem and if so how?

 

[rafiki_]

Have you tried talking to CMD aftersales? They were very useful to me when I had a BSC issue.

 

[Converging]

Yes I have tried but they cannot help.

 

[Latestarter1]

Looks like a Bosch/VDO sourced sensor, can you provide data which I cannot read on the hex flats. Lets have some data.

Seems like on in the picture has been replaced in the recent past. Even if Bosch or whoever made it have discontinued it, must be possible to cross reference it with alternative.

Another alternative is to fit Bosch/VDO sensor to keep gauge happy and fit spring loaded toggle switch to glow plug curcuit and count to three.

Final point is........Have you gone through steps to confirm sensor is the issue.

Are your instruments single or dual station??

 

[David2452]

Its an Elmwood sensor, they are in Rhode Island, may be worth looking up their email address and quoting their laser etched numbers from the flats on the sensor, they will be able to help if anybody can.

 

[Latestarter1]

Its an Elmwood sensor, they are in Rhode Island, may be worth looking up their email address and quoting their laser etched numbers from the flats on the sensor, they will be able to help if anybody can.

That MAY be the very problem. Elmwood used to be a Hawker Siddley company with plant in the North East. Real good quality bimatallic switches. However in typical Hawker Siddley style next to no investment in new profits, just creamed off the profits until the cupboard was dry.

Subsequently sold off no sure to whom, however they were in process of updating product line after changing hands, specific availability of old low volume models may be an issue.

 

[gingie]

re work

You have to cut the glow plug wiring out of the circuit.

So you connect the 2 wires for the water temp only.

The way the circuitry works is it cuts the glow plug circuit off when the engine is hot. It just means now you will have the glow circuit operating a short time on warm start up.

We have had to do this for several years now. We searched hi and low for a 4 pin and you just cant get one.

 

[David2452]

If the values were known the it may well be possible to “T” off with two separate sensors.

 

[gingie]

fix

Using the 2 wire sender i previously mentioned is the offical Mercruiser rework.

 

[Converging]

You have to cut the glow plug wiring out of the circuit.

So you connect the 2 wires for the water temp only.

The way the circuitry works is it cuts the glow plug circuit off when the engine is hot. It just means now you will have the glow circuit operating a short time on warm start up.

We have had to do this for several years now. We searched hi and low for a 4 pin and you just cant get one.

Thanks for the reply -did you replace the actual sender and if so did you have a reference for it?

 

[Converging]

Looks like a Bosch/VDO sourced sensor, can you provide data which I cannot read on the hex flats. Lets have some data.

Seems like on in the picture has been replaced in the recent past. Even if Bosch or whoever made it have discontinued it, must be possible to cross reference it with alternative.

Another alternative is to fit Bosch/VDO sensor to keep gauge happy and fit spring loaded toggle switch to glow plug curcuit and count to three.

Final point is........Have you gone through steps to confirm sensor is the issue.

Are your instruments single or dual station??

89EL007 is the reference and it is a single station sender. Bridged wires from other engine sender to proove faulty/

 

[DAKA]

IF it is the same as the 4.2L Dtronic 300 (mine is a single point sender)

Schematic M94 36 4 596 2003

The list is £89.30, however jnl engineering have them in stock @ £32.13 including delivery and VAT

Contact

Shane Simpson

JNL Engineering Limited,

Unit 10 Camberley Business Centre,

Stanhope Road,

Camberley,

Surrey.

GU15 3DP

Phone 01276 63278

Fax 01276 63432

www.jnlengineering.co.uk

ref Schematic M94 36 4 596 2003

 

[Lindegaard]

Seems like I have the exact same problem in my mercruiser 3.6D engine...
sudenly I had alarm, just by turning the key, before even starting the engine..
As I understood it could be one of 3 possible scenarios..

Oilpressure, so I found it to be a faulty oilpressure sender...
ordered 1 from germany, it's an VDO..
so changed it, and everything was fine..

then suddenly another alarm, same engine, still on running cold, so checked the oilpressure switch for faulty connection, no props, then turned to the switch in question, by pulling the black and green wire the horn shut of.. nice.. so by this I recon it must be this switch that has a problem...

I do have this question though..

If it's so hard to get your hands on, I do have another of those switches placed elsewhere on my engine, to be speciffic, when looking from aft and forward, it's located on the left side of the block, I can't see it on my engine diagram, but it has no wires attached to it, it's exactly the same switch, with the same writing on it as the faulty one, so question is:

can I simply change them, one for the other? since there are no wires connected to the one that I think is ok, it should not matter to put a faulty in that possition, or what?

I'm uploading a picture so maybe someone can tell me what it was ment for, I recon it to be for transmission fluid temperature is excessive, but I don't know..

I know this though, I want to head out to sea in this beatyfull weather, can't wait until a new replacement to arrive in weeks...

by the way sailed the boat for an half hour, and the water temp never got over 65 degrees celcius.. so it must be this switch

hope someone can help

 

[Lindegaard]

You have to cut the glow plug wiring out of the circuit.

So you connect the 2 wires for the water temp only.

The way the circuitry works is it cuts the glow plug circuit off when the engine is hot. It just means now you will have the glow circuit operating a short time on warm start up.

We have had to do this for several years now. We searched hi and low for a 4 pin and you just cant get one.

Do you know what colour that wire should have ?

 

[Mike k]

Seems like I have the exact same problem in my mercruiser 3.6D engine...
sudenly I had alarm, just by turning the key, before even starting the engine..
As I understood it could be one of 3 possible scenarios..

Oilpressure, so I found it to be a faulty oilpressure sender...
ordered 1 from germany, it's an VDO..
so changed it, and everything was fine..

then suddenly another alarm, same engine, still on running cold, so checked the oilpressure switch for faulty connection, no props, then turned to the switch in question, by pulling the black and green wire the horn shut of.. nice.. so by this I recon it must be this switch that has a problem...

I do have this question though..

If it's so hard to get your hands on, I do have another of those switches placed elsewhere on my engine, to be speciffic, when looking from aft and forward, it's located on the left side of the block, I can't see it on my engine diagram, but it has no wires attached to it, it's exactly the same switch, with the same writing on it as the faulty one, so question is:

can I simply change them, one for the other? since there are no wires connected to the one that I think is ok, it should not matter to put a faulty in that possition, or what?

I'm uploading a picture so maybe someone can tell me what it was ment for, I recon it to be for transmission fluid temperature is excessive, but I don't know..

I know this though, I want to head out to sea in this beatyfull weather, can't wait until a new replacement to arrive in weeks...

by the way sailed the boat for an half hour, and the water temp never got over 65 degrees celcius.. so it must be this switch

hope someone can help

I may be off beam here but my alarm always sound at the ignition stage and stops on starting the engine because all the pressures get up to normal- am i missing something?

 

[Lindegaard]

I may be off beam here but my alarm always sound at the ignition stage and stops on starting the engine because all the pressures get up to normal- am i missing something?

no, my one is doing so, but only because my mecanic put it back that way, I was getting crazy, so had it removed.. but now back again, it's supposed to do so..

the one that I do have alarm on now, is not hooked up that way, and still carries the alarm after starting the engine..

but yours are normal..

 

[DAKA]

if there has been a neutral safety fault it is possible that someone has crosswired your ignition live earth with a constant live earth, it sounds a bit like someone has been changing wires round this area.
This would cause your alarm to sound.

after starting pull the starter relay out and see what happens.

another possibility, if you have a gear box disconnect the temp sender on that too.

 

[Lindegaard]

if there has been a neutral safety fault it is possible that someone has crosswired your ignition live earth with a constant live earth, it sounds a bit like someone has been changing wires round this area.
This would cause your alarm to sound.

after starting pull the starter relay out and see what happens.

another possibility, if you have a gear box disconnect the temp sender on that too.

if the answer was ment for me:

my one engine, has never had this "normal" buzz before startup..

I was told the reason for it to be there was so that one would know that the buzzer worked, since my panel has no test button for this..

therefore, when installing new heatexchanger on my other motor, the mec rewired or whatever, so that it has this BUZZ.. but he only did it at that one engine..

everything had been running smoothly all last season, only just one week before taking the boat out of water, theese things started..

no other senders, gearbox etc..

forgive me my unknowledgement on this, but how do I check for live earth and constant live earth ?

forgive my poor english too, hope you all know what I mean..

 

[DAKA]

This is a very basic test, if you dont know how then you MUST get a mechanic in.

You attach a multimeter or 12v light to a constant positive feed (battery terminal for example).

You then test to see if your starter relay earth lights the bulb, it shouldnt but I suspect it does.

You then turn your ignition on to see if the bulb lights which it should.

It is common to find DIY and bodge mechanics have by passed the neutral safety switch , if they have simply earthed the starter relay then it would cause the buzzer to sound after starting and remain on.

If your engine is the same as the OPs then you have at least two earth wiring circuits in your loom , one of which is obsolete for your engine .



Just one of many things, you need a good mechanic.

 

[Lindegaard]

This is a very basic test, if you dont know how then you MUST get a mechanic in.

You attach a multimeter or 12v light to a constant positive feed (battery terminal for example).

You then test to see if your starter relay earth lights the bulb, it shouldnt but I suspect it does.

You then turn your ignition on to see if the bulb lights which it should.

It is common to find DIY and bodge mechanics have by passed the neutral safety switch , if they have simply earthed the starter relay then it would cause the buzzer to sound after starting and remain on.

If your engine is the same as the OPs then you have at least two earth wiring circuits in your loom , one of which is obsolete for your engine .



Just one of many things, you need a good mechanic.

Well, see in my scenario, it ran all last year without this buzz when turning the key before starting, suits me well... on the one engine, so the buzz it makes now both before and after start must be a faulty sender... will try to do as you suggest later this afternoon, but first I will try to interchange the 2 switches I have since 1 of them is not in use anyways...

Best regards

Claus.