Coolant pressure test inquiry

[BumbleBoi]

Hello all,

I did a coolant pressure test today on my high circuit reservoir.

I started with around 1.5bar per the manual, and after 2 hours the pressure dropped to 1.4bar.

I'm not sure how to interpret the manual, but is this pressure lost an acceptable rate/mount?

I was thinking the manual is stating to observe the pressure for ~2minutes and look for a maximum of 0.1bar drop.
I did 2hrs just to see.

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[concept]

That is a bit ambiguous. Perhaps it should've stated "maximum DROP in pressure". If so, you have passed the test.

Also, would the drop continue after additional wait time?

 

[BumbleBoi]

I

That is a bit ambiguous. Perhaps it should've stated "maximum DROP in pressure". If so, you have passed the test.

Also, would the drop continue after additional wait time?

I only waited 2 hrs.
The reason I'm checking is because Blackstone suspect there is a coolant leak in my oil from my previous 2 analysis
Its kinda a bizarre situation, not sure what to do or if it's an actual problem

 

[concept]

Extending the wait time may help. Typically, there are a few ways that coolant may mix with oil:

1. Blown Head Gasket or Cracked Cylinder Head: These can allow coolant to leak into the oil passages.
2. Damaged Engine Block: A cracked or damaged engine block can create a pathway for coolant to leak into the oil system.
3. Faulty Oil Cooler: If the oil cooler is damaged, it could potentially allow coolant to mix with the oil.

What year is and how many miles are on, your car?

 

[BumbleBoi]

2022,20k miles

 

[lucky phil]

Hello all,

I did a coolant pressure test today on my high circuit reservoir.

I started with around 1.5bar per the manual, and after 2 hours the pressure dropped to 1.4bar.

I'm not sure how to interpret the manual, but is this pressure lost an acceptable rate/mount?

I was thinking the manual is stating to observe the pressure for ~2minutes and look for a maximum of 0.1bar drop.
I did 2hrs just to see.

I don't understand why you are measuring the drop over a 2 hour period when the manual calls for a 2 minute test like most other cars do? You might want to consider that the volume of air in the header tank is very small so the pressure is going to vary noticeably with small temp changes and also there will be a small initial temp increase and therefore a false pressure indication due to the compression of the air with the pump which will dissipate over time. When doing these types of tests over a long duration when thats whats called for you always pressurise and wait for a time before taking a baseline reading for this reason. The 2 min test is to eliminate the variables like this temp and pressure increase and decreases due to compression and subsequent cooling and volume changes due to ambient changes in temperature and stretch of cooling hoses and a few other variables.
This also raises another point I posted a while back regarding oil sample analysis. Basically my position is that it's primarily designed for commercial use not individual owner use and what you are experiencing is what I outlined previously. Assuming the engine isn't using coolant and shows no physical cooling system issues then the oil analysis is taking you down a rabbit hole you probably don't need or want to go down. Sodium is elevated but Potassium isn't which would be a marker for coolant leakage. Sodium on it's own, not so much. The other issue is you have no baseline for the oil sample only Blackstone historical data on a particular oil additive baseline. You should really send a clean oil sample every time if you want to be absolutely sure. But like I said Analysis results are great when they come back looking good but when you have a " we don't quite understand result" and you have no other operating issues to support a hypothesis all you are going to do is lose sleep and go down a rabbit hole.

Phil

 

[BumbleBoi]

I thought the same about the oil analysis. I didn't understand how I was suppsed to use the information provided by Blackstone... And it doesn't look like Blackstone knows what I should do either since they stated to send more samples in the future.
I spent a bit of time stratching my head, asking "does this mean I have to replace something in the engine or rebuild it?" or "does this mean I have to fix something in the future??"
I also took the oil from the drain plug, which potentially introduced contamination into the oil sample.

I pressurized the high temp circuit for 2hrs just out of curiosity on what the readings would do. I didn't know what to expect for the pressure.
I just let the car cooled down overnight to avoid pressure reading fluctuation from engine cooling down. That's all the precaution I took.

 

[lucky phil]

I thought the same about the oil analysis. I didn't understand how I was suppsed to use the information provided by Blackstone... And it doesn't look like Blackstone knows what I should do either since they stated to send more samples in the future.
I spent a bit of time stratching my head, asking "does this mean I have to replace something in the engine or rebuild it?" or "does this mean I have to fix something in the future??"
I also took the oil from the drain plug, which potentially introduced contamination into the oil sample.

I pressurized the high temp circuit for 2hrs just out of curiosity on what the readings would do. I didn't know what to expect for the pressure.
I just let the car cooled down overnight to avoid pressure reading fluctuation from engine cooling down. That's all the precaution I took.

This is a major mistake. never take samples from the bottom of the sump always mid stream. I've had plenty of experience monitoring cooling systems over the years and this is what I would do. If you are going to keep doing analysis then next time send a sample of unused oil left over from the previous change with the sample. Take the sample mid stream with a warm engine during the regular oil change. Cleanliness is obviously paramount. Since the Jet age began all engineers carried two screw drivers around with them always. A #2 phillips for just about every panel on the aircraft and a 10 inch flat blade for opening engine cowls and engine oil cans. We used to use 1 quart sealed cans and opened them with a punch on the top on each side with a flat blade and pour it in from the can. Engines could take 20 cans sometimes after a transatlantic flight. We all did this for decades until oil analysis showed the can material in the oil from opening with a flat blade. After that we needed another methodology to open oil cans. So cleanliness is paramount. Such as cleaning the sump plug area and cap area if it needs it before the sample is taken and oil filled.
Just drive the car and relax. if it starts using coolant, emits white smoke during cold starts for a short time or exhibits "mayo" in the oil or overheats or any other cooling system problem then you need to take some action. If this car had to actually earn it's keep as a commercial vehicle and down time was money it would simply be put on a "watch " list and monitored. People wouldn't be worrying about it and thats the difference between commercial and private interests. One is impersonal and the other the opposite. One group won't lose sleep and the individual probably will. That's why I don't bother with it and believe me I'm detail orientated. Commercially It would need to exhibit a lot worse results or at least conclusive results and or multiple symptoms before action was taken.
Interesting to see in the manual the traces of coolant around the cap that people worry about is completely normal according to Toyota/BMW.

"When driving at high ambient temperatures, the design may cause the pressure relief valve in the reserve tank cap sub-assembly to open slightly and air to escape together with dissolved coolant. This coolant vapor condenses on the surface of the radiator reserve tank assembly and leaves traces of coolant when the vehicle has cooled down. These traces of coolant do not indicate whether the reserve tank cap sub-assembly is defective or not"

Phil

 

[BumbleBoi]

Thank you for the feedback

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