Priming oil pump on hybrids

[bathtub tom]

I've read that Yoyota hybrids don't have a self-priming oil pump and that during an oil change there's only a limited time to re-fill the sump after draining. Is there any way for the home mechanic to prime the pump?

[TonyHSD]

Never heard of anything like that from knowledgeable mechanics, perhaps a question for the car care nut in USA. 👍

[forkingabout]

I get the feeling someone's been reading a thread over on the Honest John forum.

[anchorman]

3 hours ago, bathtub tom said:

I've read that Yoyota hybrids don't have a self-priming oil pump and that during an oil change there's only a limited time to re-fill the sump after draining. Is there any way for the home mechanic to prime the pump?

Why does it need to be primed.  It will prime when the engine runs like any other internal combustion engine.  If you want to force the engine to start, turn the heating right up or down in a hot day.  

[TonyHSD]

Previous generation hybrids have maintenance mode in which the ice start and work as long as you keep the car in this mode. It’s specifically designed for warming up the engine prior to oil / transmission fluid changes or diagnostic for engine live data parameters, emissions etc. 

Very likely gen 4 hybrids with M series engines to have the same or similar thing but I haven’t work on any yet and can’t say for sure. I am aware some of them has an electric oil pump but as long as there is oil in the pan the car will do it’s job to ask the pump to pump oil and rise pressure. For oil change it’s the same, drain nd refill as on any other ice. 👍

[flash22]

In a word, no

it's a mechanical pump, it will self prime, if you drain the oil and leave it drained for a few days then fill it up, with a standard engine you just crank it in flood clear (full depressed throttle)

 

with a hybrid the electric motor turns over the engine - as soon as the crank turns its building oil pressure, the engine will not start until the ecu sees the oil pressure meet its target as soon as it fires it's at full pressure

[flash22]

Yes you have a service/dyno mode in techstream, most scan tools can also do it

[bathtub tom]

Here's the bit I read:

"they are using variable displacement pumps, which I gather the new Prius has and is ECU controlled like the water pump. it assists in heating up the engine from cold faster to reduce emissions and keeps a more controlled temp across the whole engine which the Prius for one needs as its not run as often."

"apparently if an oil change is done the change should be done in a certain time to prevent oil drain off of the pump, otherwise they have to be primed, though I couldn't see how its done."

Apparently copied from: The car care nut on youtube. An American.

[APS]

This doesn't make sense. Oil drains to the oil pan as soon as the engine stops. So, unless the oil pump is submerged in the oil in the sump, the same conditions would happen every time the engine stops.

As far as I'm aware the variable displacement pump is more about controlling the output of the pump through a valve. This way they can reduce amount of energy used by the pump and thus increase fuel economy. The pump still functions as normal. 

In short, I would not worry.

[flash22]

https://toyota-club.net/files/faq/20-08-01_faq_df_r3_en.htm

"Oil pump is of traditional design, built into the chain cover and driven directly by the crankshaft."

[RickyC]

Mmm.  Also on the hybrid engine? Oil is used also by the electric engines so oil pump must work also when ICE is off. 

[flash22]

yes the only differences is the hybrid uses port injection (EFI) and the AC and water pump is electric whereas the standard engine is DI and has a balance shaft with standard ancillaries

the electric motor/starter/alternator (MG1 and MG2) is in the gearbox on the hybrid, so is cooled by that fluid

[bathtub tom]

2 hours ago, APS said:

This doesn't make sense. Oil drains to the oil pan as soon as the engine stops. So, unless the oil pump is submerged in the oil in the sump, the same conditions would happen every time the engine stops.

 

AIUI that's the problem. Once the oil is drained, it's the residual oil in the pump that primes it. If that oil is also allowed to drain out, then the pump can't prime itself, despite the sump oil level.

[anchorman]

12 hours ago, bathtub tom said:

AIUI that's the problem. Once the oil is drained, it's the residual oil in the pump that primes it. If that oil is also allowed to drain out, then the pump can't prime itself, despite the sump oil level.

There is some nonsense flying about in this forum.  

[anchorman]

12 hours ago, flash22 said:

yes the only differences is the hybrid uses port injection (EFI) and the AC and water pump is electric whereas the standard engine is DI and has a balance shaft with standard ancillaries

the electric motor/starter/alternator (MG1 and MG2) is in the gearbox on the hybrid, so is cooled by that fluid

The current hybrid uses both port and direct injection doesn’t it?

[Cyker]

The M15A-FXE in the hybrid Yaris is port injection only, but the M15A-FKS in the non-hybrid is, I believe (but don't quote me on it!), both, or maybe just direct injection.

I think the M20A-??? in the Corolla is both tho'.

 

[flash22]

FKS is direct injection, the hybrid is EFI

Dry weight: 85.1 (D-4) / 87.3 (EFI)
Firing order: 1-2-3

M15A-FKS (1.5 D-4 DVVT-iW) - transverse layout, direct injection, DVVT-iW, Miller cycle operation mode. Applications: Toyota Yaris 210, Yaris Cross

M15A-FXE (1.5 EFI DVVT-iE) - for hybrids, transverse layout, multipoint injection, DVVT-iE, Miller cycle operation mode. Applications: Toyota Yaris 210 Hybrid, Yaris Cross Hybrid

M20 is direct injection

https://toyota-club.net/files/faq/18-03-20_faq_df_r4_eng.htm

 

[APS]

21 hours ago, bathtub tom said:

AIUI that's the problem. Once the oil is drained, it's the residual oil in the pump that primes it. If that oil is also allowed to drain out, then the pump can't prime itself, despite the sump oil level.

Some reasoning:

• I don't see engine failures due to unprimed oil pumps being raised here as a rampant issue
• Oil pumps generally don't need priming. They are high precision pumps that generate suction just from the thin oil film on its components
  • Contrast this to impeller pumps like a water pumps that must be primed before they can create any kind of negative pressure (suction)
• Engine oil is clingy and will leave a film on internal surfaces for long periods of time; months, years
• Toyota would avoid designing an engine that required very unusual and risky service procedures as it would be very costly in the long run when service technicians inevitably mess up. (a core principle of the Toyota production system is to standardise work; stick to processes, make it "fool proof").
• I've seen no technical bulletin or detailed description of the 'problem', with a root cause analysis
• If it originated from the car care nut, I'd reach for the salt

I'm happy to be wrong and learn something new. 

[flash22]

Only ever had to prime an oil pump on an engine i was rebuilding with some sort of grease, it was a long time ago tbh

Apart from old British motorcycles never had the need to bleed/prime an oil system - IIRC the M15a- uses a 0w8 oil what's almost as thin as water

Quote

Once the oil is drained, it's the residual oil in the pump that primes it. If that oil is also allowed to drain out, then the pump can't prime itself, despite the sump oil level

this is simply negated by a one way valve in the pickup

[Cyker]

Given that we've had people leave their cars long enough for the 12v Battery to drain multiple times and none of them have experienced catastrophic engine failure I think it's safe to assume it's not a major problem  

[bathtub tom]

5 hours ago, Cyker said:

Given that we've had people leave their cars long enough for the 12v battery to drain multiple times and none of them have experienced catastrophic engine failure I think it's safe to assume it's not a major problem  

It's alleged that the problem occurs when the sump is drained and not re-filled within a certain time. Nothing to do with the car standing unused!

[anchorman]

I don’t know what all the fuss is about.  It’s just a regular crank driven oil pump inside the timing case.  When the oil is drained in any car the oil stays full in most of the galleries and the oil pump and even if the oil did drain from the oil pump (usually only if it has been opened up for repair work) it will self prime if it is submerged in oil.  I personally would remove the spark plugs and spin the engine on the starter if I knew it had been emptied but it would prime if started.  What’s happened here is somebody has read something they don’t understand regarding an older vehicle with a remote electric pump that might need priming and assumed it applies to later models.