Coolant loss -- unable to determine source

[MaximaGuy]

I have a small coolant loss (150K on the orignal water pump) and haven't root caused from where it could leak. The timing cover right behind the tensioner and just below the water pump is wet and with mud accumulated it is quite difficult to determine it is oil/grime picked up from the highways or actually a leaking water pump. BTW is there some chemical that can react with coolants when sprayed on the surface (like luminol picks up blood)....

Based on the previous coolant losses, pl. pitch in ur comments to a probable cause of leak (radiator and all radiator hoses are new).

 

[Mookitty]

Add some UV dye to the coolant. Then blacklight the engine in a few days. If you don't see glowing spots, you've got an internal leak.

You can get small bottles of UV dye at most parts houses. AZ has it with the A/C stuff.

 

[Paul56]

Originally Posted By: MaximaGuy
I have a small coolant loss (150K on the orignal water pump) and haven't root caused from where it could leak. The timing cover right behind the tensioner and just below the water pump is wet and with mud accumulated it is quite difficult to determine it is oil/grime picked up from the highways or actually a leaking water pump. BTW is there some chemical that can react with coolants when sprayed on the surface (like luminol picks up blood)....

Based on the previous coolant losses, pl. pitch in ur comments to a probable cause of leak (radiator and all radiator hoses are new).


Scrape some of that accumulation off where it is wet and take a sniff... does it smell like coolant?

Along with the timing belt I replaced my water pump last summer and found evidence of seepage on the pump.

 

[alreadygone]

CLEAN the accumulation! Then watch for fresh leak.

Bob

 

[mechtech2]

Sounds like a WP leak.

 

[severach]

Finding leaks is one of the reasons you clean an engine.

 

[MaximaGuy]

OK. Finally figured out that there indeed is a leak and eventually making it to the oil. I threw in some UV dye into the coolant and after a week it showed up in the oil cap and some oil residue near the oil pressure switch.

I will be sending the oil for analysis to be sure the second time around.

Now as I said earlier I have 150K on the motor and have suspected the pump. Could a weak or leaking pump dump coolant ever so slowly into the oil?

 

[Donald]

I cannot see how a pump would cause the leak. I would assume a head gasket as the first cause.

 

[brianl703]

If the timing cover gasket is leaking and seals both coolant and oil, it could allow coolant into the oil.

 

[PT1]

This scenario would be trade in time for me.

 

[MaximaGuy]

OK. I shall give some history of the problem to help get a better perpective of what could be going wrong in the engine.

First, thanks to my monkeying with coolants I had a partially clogged radiator. There was a brief period of overheating (never close to levels it blew any smoke etc) only when the engine was climbing a hill etc where the max load was put on the engine and least flow was experienced inside the radiator. It took me close to 2 months to clear the mess and finally dropping in a new radiator. That solved all the problems and even did an UOA of the oil after that and a compression test to check the head gasket. So in short I saved a rebuild/head gasket blowout.

Now, there is a ever slight leak of coolant into the oil and not the other way around. If the HG was screwed the oil and coolant would mix both ways and it would be obvious in the coolant (with oil) and in the oil (with coolant).

If the pump was fine but the o-rings failed(ing) then the coolant would pass both the rings and make it to the timing cover and then to the oil which could explain why coolant is present in the oil and not the other way around.

I wanted to open the pump cover plate and see if coolant actually made it thro the o-rings into the timing cover/case for which it is quite an exercise. The tensioner has to come off and all that [censored] and it is a 2 hr exercise. If I have to take it to the dealership and shell out $150 then they might else well do all the checks.. But what [censored] me off it when I took my vehicle to the dealership for the first heating issue they promptly said there was nothing they could pin-point on. It was a chance bet to shell out $150 for an radiator that proved a partially clogged radiator.

Now coming to the gaskets itself, the cylinder head gaskets are all metallic in nissans and the valve cover gasket and head gasket may be one piece (honestly don't know) and based on the repair manual the valve cover gasket only seals the oil and not coolant. The head gasket may seal the coolant, I have seen in other vehicles where the gaskets are semi-metallic/synthetic cork based compound that not only cover the timing cover but also the cylinder heads, one gasket that covers all.

Hope this helps. I will take it to the dealership and have then take care of it.

 

[bullwinkle]

Originally Posted By: MaximaGuy
OK. I shall give some history of the problem to help get a better perpective of what could be going wrong in the engine.

First, thanks to my monkeying with coolants I had a partially clogged radiator. There was a brief period of overheating (never close to levels it blew any smoke etc) only when the engine was climbing a hill etc where the max load was put on the engine and least flow was experienced inside the radiator. It took me close to 2 months to clear the mess and finally dropping in a new radiator. That solved all the problems and even did an UOA of the oil after that and a compression test to check the head gasket. So in short I saved a rebuild/head gasket blowout.

Now, there is a ever slight leak of coolant into the oil and not the other way around. If the HG was screwed the oil and coolant would mix both ways and it would be obvious in the coolant (with oil) and in the oil (with coolant).

If the pump was fine but the o-rings failed(ing) then the coolant would pass both the rings and make it to the timing cover and then to the oil which could explain why coolant is present in the oil and not the other way around.

I wanted to open the pump cover plate and see if coolant actually made it thro the o-rings into the timing cover/case for which it is quite an exercise. The tensioner has to come off and all that [censored] and it is a 2 hr exercise. If I have to take it to the dealership and shell out $150 then they might else well do all the checks.. But what [censored] me off it when I took my vehicle to the dealership for the first heating issue they promptly said there was nothing they could pin-point on. It was a chance bet to shell out $150 for an radiator that proved a partially clogged radiator.

Now coming to the gaskets itself, the cylinder head gaskets are all metallic in nissans and the valve cover gasket and head gasket may be one piece (honestly don't know) and based on the repair manual the valve cover gasket only seals the oil and not coolant. The head gasket may seal the coolant, I have seen in other vehicles where the gaskets are semi-metallic/synthetic cork based compound that not only cover the timing cover but also the cylinder heads, one gasket that covers all.

Hope this helps. I will take it to the dealership and have then take care of it.
Not necessarily-if the coolant only leaked under pressure-then, IMHO, it would be difficult to get oil into the coolant. From your description, & not knowing what engine you have (AL head/cast block?), if it was ran hot, a head gasket/warped head sounds likely (my old '91 Stanza 2.4 did it), esp. w/stamped steel head gasket. You're doing the right thing getting it fixed, glycol in oil=rapid bearing failure.