Leaking Coolant Level Sensor

[Clem]

Hi guys,

I need a few words of advice please. Some years back Graham Cumming fitted a coolant loss sensor to my 4.8 GRX. Picture attached. Recently I noticed that coolant was being lost from that area. At first I thought it was leaking from around the threads of the stainless steel bolt. I sealed that with a little bit of PTFE tape but upon closer inspection realised that it is leaking from the underside of the joint between the pipe and the sensor housing that is closest to the radiator. In fact it is leaking quite significantly. I have tried replacing the clamps with new Norma clamps but to no avail. It continues to leak. And fairly severely now. I am a little bit at a loss as to how to solve the problem other than by purchasing a new radiator hose from Nissan and fitting it. I suppose then I could remove the coolant loss sensor and inspect it properly to see what has gone wrong. For the record this is the first and only time I have had any cooling system problems with this vehicle. In fact any material problems at all other than warped brake discs which needed skimming.

Any thoughts or advice would be much appreciated.

Best,
Clem

[iandvl]

Clem,

I'm not an expert. However, looking at the photograph it seems almost as if the sensor housing is not totally aligned with the pipes. The radiator hose seems to be making "bubbles" (bubbles for want of a better word) behind the clamps. Perhaps it is just the photograph, and these may just be as a result of the flange on the sensor housing ?

My thought, however, is that if it continues leaking even with new clamps, it is probably time for new radiator hoses.

I'd suggest getting a new radiator hose, removing the existing hose. Inspect the sensor housing to make sure it is not damaged. You can then make a call to fit the new hose as-is, or cutting it down to accommodate the sensor housing.

A side note: You're not stuck with Nissan only. Terrain Tamer also provide excellent radiator hoses. Chat with Tinus. Good luck, and please give feedback when done.

A final thought: Please make sure you bleed the cooling system properly once done.

[AndriesS]

would also check if there is not the tiniest of crack in either ether hose or connector unit. `The engine half of the hose can take a bit of flex why not cut the radiator section 5-10mm shorter and see if it stops?

[Clem]

Clem,

I'm not an expert. However, looking at the photograph it seems almost as if the sensor housing is not totally aligned with the pipes. The radiator hose seems to be making "bubbles" (bubbles for want of a better word) behind the clamps. Perhaps it is just the photograph, and these may just be as a result of the flange on the sensor housing ?

My thought, however, is that if it continues leaking even with new clamps, it is probably time for new radiator hoses.

I'd suggest getting a new radiator hose, removing the existing hose. Inspect the sensor housing to make sure it is not damaged. You can then make a call to fit the new hose as-is, or cutting it down to accommodate the sensor housing.

A side note: You're not stuck with Nissan only. Terrain Tamer also provide excellent radiator hoses. Chat with Tinus. Good luck, and please give feedback when done.

A final thought: Please make sure you bleed the cooling system properly once done.

Hi Ian, thank you very much. The car is now 9 years old, so some things will be showing a bit of age. But less than 80k km. May be time for several new hoses.

[iandvl]

I had several water pipe issues a year or two ago - presumably aged rubber tubes. The first pipe burst early in January 2019. After getting a replacement pipe, I fixed next to the road, topped up water and bled motor. At the end of January, the second pipe burst. At the time, I opted to replace every single coolant hose. I've had zero issues since... :) There is a thread about this here: viewtopic.php?t=8225

Most coolant pipes are very generic, with the exception of the radiator and heater hoses. You get radiator hose kits from Terrain Parts, but I am unsure whether they have heater hoses, and these might dealers only. The only other non-generic pipe is a right-angled pipe underneath / inside the intake manifold somewhere which connects to the oil cooler. There is, however, an alternate part one can use. The part number is in the post mentioned above. I think that alternate part number is for a Quantum, which makes it generic enough and available at pretty much any vehicle spares shop...

Apart from radiator and heater hoses, all pipes are super cheap. It is just a super horrible job to do.

If you opt to replace all the coolant hoses, please also make sure the oil cooler is also not blocked. There is a thread about this here: viewtopic.php?t=8372

Both posts above are for a TB45 (not a TB48), but should give some idea of what and where the various components are.

[Clem]

would also check if there is not the tiniest of crack in either ether hose or connector unit. `The engine half of the hose can take a bit of flex why not cut the radiator section 5-10mm shorter and see if it stops?

Thanks Andries. Nothing is externally visible. At least not given the angle and lighting at which I see it. I suspect that there is a hairline crack somewhere. But I will only know once I get the thing out. I might do exactly what you suggest. But you know the importance of the reliability of this part… So I am inclined to rather simply replace the hose.

[Clem]

I had several water pipe issues a year or two ago - presumably aged rubber tubes. The first pipe burst early in January 2019. After getting a replacement pipe, I fixed next to the road, topped up water and bled motor. At the end of January, the second pipe burst. At the time, I opted to replace every single coolant hose. I've had zero issues since... :) There is a thread about this here: viewtopic.php?t=8225

Most coolant pipes are very generic, with the exception of the radiator and heater hoses. You get radiator hose kits from Terrain Parts, but I am unsure whether they have heater hoses, and these might dealers only. The only other non-generic pipe is a right-angled pipe underneath / inside the intake manifold somewhere which connects to the oil cooler. There is, however, an alternate part one can use. The part number is in the post mentioned above. I think that alternate part number is for a Quantum, which makes it generic enough and available at pretty much any vehicle spares shop...

Apart from radiator and heater hoses, all pipes are super cheap. It is just a super horrible job to do.

If you opt to replace all the coolant hoses, please also make sure the oil cooler is also not blocked. There is a thread about this here: viewtopic.php?t=8372

Both posts above are for a TB45 (not a TB48), but should give some idea of what and where the various components are.

Thank you Ian. I wil check it out. I will have a look at the general condition of the hose once I get it out of the engine and based upon that make a decision as to whether it is time to replace all hoses. Looking at it externally, it is still in good condition. There is no clearly apparent hardening or cracking yet. I suspect something has gone wrong where the hose was split to fit the sensor housing. Either that or the sensor housing itself has developed a hairline crack. BUt will see and update here.

As a point of interest, what was the approximate age and mileage when you needed to replace all the hoses? Just as a rough rule of thumb for my own purposes. It's been many years since I have last had replace a full set of hoses on any machine. But then again, the Patrol has been my primary vehicle for many years as well. :-)

[iandvl]

Thank you Ian. I wil check it out. I will have a look at the general condition of the hose once I get it out of the engine and based upon that make a decision as to whether it is time to replace all hoses. Looking at it externally, it is still in good condition. There is no clearly apparent hardening or cracking yet. I suspect something has gone wrong where the hose was split to fit the sensor housing. Either that or the sensor housing itself has developed a hairline crack. BUt will see and update here.

As a point of interest, what was the approximate age and mileage when you needed to replace all the hoses? Just as a rough rule of thumb for my own purposes. It's been many years since I have last had replace a full set of hoses on any machine. But then again, the Patrol has been my primary vehicle for many years as well. :-)

I have no idea what mileage this would have been. I probably made a note of this in my service book, so I can probably check that when I am near it. The vehicle would have been 18 years old in 2019 (2001 model).

[Clem]

Eish. No stock with Nissan SA. 4 to 5 week backorder...

[iandvl]

Eish. No stock with Nissan SA. 4 to 5 week backorder...

Partsouq has stock - https://www.partsouq.com

HOSE-RADIATOR,UPPER (21501VC200) - USD 27.18

Although they do not have stock of the standard part (21503VC200) for the lower hose, they do have stock of substitute part number (21503VC20A) - also Nissan.

HOSE-RADIATOR,LOWER (21503VC20A) - USD 23.41

You'll pay a few ZAR for shipment and customs, but you'll probably have new hoses before the weekend.

Just double check the part numbers (enter your VIN number). These part numbers come from the 2003 4.8 Patrol I used to have which the ex-wife wrote off.

Edit: Or chat with Tinus about Terrain Tamer.