TIA for suggestions on odd phenomena: Loss of oil pressure until oil warms?

OldSkool · 07-07-2008, 06:42 PM

For the first 15 minutes or so, (less than 20 for sure) I get lower oil pressure
at RPM's above idle. It is nearly bottomed out on the gauge at 3K. When the
oil warms up (several minutes after the coolant, makes sense I guess) Oil
pressure resumes to normal and stays there even at higher RPM's. (5K+)
Is this common and can I do anything to prevent starvation of oil when cold?
I just want to know if this is a common "Toy" problem and what you all did.

More input after your ideas... LMK!

Mista 2 · 07-08-2008, 07:54 AM

What oil do you have in it at the moment? your oil could just be too thin. This one is a stab in the dark but your oil pump might be on the way out and cant move the thin (cold) oil. are you getting any loud ticking noises or anything else you should add?

mr2magic · 07-08-2008, 09:37 AM

Correct me if I'm wrong but his oil would get even thinner when warm resulting in even less pressure by your reckoning.

When did you last change oil, filter and pump? Could your oil be to thick until warm?

rousegk7 · 07-08-2008, 12:16 PM

Quote:

Originally Posted by mr2magic

Correct me if I'm wrong but his oil would get even thinner when warm resulting in even less pressure by your reckoning.

When did you last change oil, filter and pump? Could your oil be to thick until warm?

I think Mista was backwards. Oil gets thinner the warmer that it gets warmer, but his theory was right. The oil pump might not have enough power to push the cold oil through the engine until it reaches a certain viscosity. Also how "cold" is the car? Are you in the antarctic, or is it sub-60 in florida?

OldSkool · 07-08-2008, 07:40 PM

Quote:

Originally Posted by mr2magic

Correct me if I'm wrong but his oil would get even thinner when warm resulting in even less pressure by your reckoning.

When did you last change oil, filter and pump? Could your oil be to thick until warm?

Dude is seemingly right, I have had ~65* F nights and the oil is 15w-40 diesel spec.
It gets better as it warms up, and my dumb butt added 5 quarts before I looked at
the Haynes manual the previous owners graciously provided. 3.6 quarts??? So I drained
about 1/2 a quart or so and called it good. Perhaps the oil is also "roping the crank"
when it is thicker. I planned a quick drain interval for the first change anyway, I used
the old filter (it had just 1500 miles on it according to the window oil sticker) and
I'll use the recommended weight this time and keep my eyes on that gauge and
check the pump next I suppose. Shouldn't be too hard to change.
Some cars just cannot tolerate anything but the recommended weight (and volume!)

Thanks guys, I'll take these suggestions under consideration!

BRoman · 07-08-2008, 07:52 PM

Filter change couldn't hurt...a clogged filter could do this

If you're seeing no pressure and no warning light, could be the gauge. Grounding the wire to the sensor should send the gauge to 100%. Just some things to try

OldSkool · 07-08-2008, 07:57 PM

Quote:

Originally Posted by BRoman

Filter change couldn't hurt...a clogged filter could do this

If you're seeing no pressure and no warning light, could be the gauge. Grounding the wire to the sensor should send the gauge to 100%. Just some things to try

Kewl, the gauge crossed my mind while driving, guess I could check that too!
THX

Mista 2 · 07-09-2008, 05:56 AM

I dont have anything backwards. When the oil is cold and thin it wont build up to he same pressure that warm oil will. You never said the oil pressure at 1,000 RPM. It could just be your oil pressure switch being dicky or because you are using diesal and a reused filter it could have built up crap on it. I would do an oil flush, change the filter and put a magnetic sump plug it. While the oil is out i would have a look at the oil pump if you can.

For those that really want to know oil starts off thin so it can get to the moving parts of your engine and if it is a multigrade will thicken up as it get hotter. As for as the viscocity that 4AGE's you can put anything you want in. you will just need to remember that too thin and you wont get the oil pressure that is ideal and too thick and you'll end up burning it off as it get drained into your intake.

Why did you not drain the 1.4q to begin with?

mr2magic · 07-09-2008, 08:08 AM

^Sorry but you are so wrong it hurts! Cold oil is most definately not thinner than warm or hot oil! The viscosity of oil is merely a measure of how much the thickness of the oil changes/decreases with increased temperature!

Please be informed before writing something like that.

mr2magic · 07-09-2008, 08:20 AM

By the way you can almost deduct what I said by looking at the oil weights:

0W - 40 - Viscosity index 0 at Winter temp-40 at operating temp
5W - 40 - Viscosity index 5 at Winter temp-40 at operating temp

(Winter temp = 0 °F)

OldSkool · 07-09-2008, 05:36 PM

Quote:

Originally Posted by Mista 2

Why did you not drain the 1.4q to begin with?

I drained ~.5 quarts, for a total of ~ 4.5 Q or 1 quart over the recommended amount.
There is a guy, Louis Lapointe over at lube-dev.com that states that any engine
can carry 1 quart extra in the crankcase, (in his considerable experience I suppose)
but I can see where an engine such as this perhaps could not, high RPM engines
tend to have different oil control measures and means than standard lo-po setups.
I'm sticking strictly to the book on this next oil change! I planned on a quick change interval anyway.

tjmr2 · 07-10-2008, 01:21 AM

Mista 2: Put a bottle of oil in your freezer, leave it set overnight and try to pour it out, then get back to us.

Oldskool, You didn't mention that the engine rattled or made bad noises while it shows low pressure so thats the good news, the bad news is according to the Toyota manual aka BGB the following can cause a loss of oil pressure: 1. Oil leakage - nope 2. Relief valve faulty - possible 3. Oil Pump Faulty - possible but unlikely as it pumps thinner oil, telling us the clearances in the pump are ok 4. Poor quality engine oil, don't know what brand you are running so possible but unlikely 5. Crankshaft & or Connecting rod faulty, nope you have pressure when hot not cold, 6. Oil filter clogged, possible hotter thinner oil is flowing thru plugged media that the thick cold oil won't.

If the oil pressure gauge didn't move it might be faulty, but since it changes once the car warms up it's probably ok.

I'd start with the easy stuff first, change the oil and filter, use a "Toyota" filter from the dealer (no I'm not associated with Toyota in any way except I own one), and a good quality name brand oil. Where you live probably a 10w40 this time of year.

The really bad news is if it's an relief valve or oil pump you get to drop the oil pan, remove the inlet, then remove the alternator belt, AC belt, the timing belt, and the front crank pulley before you can remove the oil pump.

Good luck, we look forward to hearing your resolution.

OldSkool · 07-10-2008, 06:53 PM

Oops, forgot to say, no odd engine noises at all.

If it is a pump, at least I have all the tools.
I am somewhat of an engine guru after all

I am doing the oil change Friday nite.

Mista 2 · 07-10-2008, 10:47 PM

A monograde is an oil whose viscosity is defined at only one temperature, either high or low. A multigrade must meet both high and low temperature viscosity requirements simultaneously. This makes multigrades an easy and popular year-round choice for drivers who experience hot summers and harsh winters. They are easily recognized by the dual viscosity designation (i.e. 10W-30 where the 10W is the low temperature, or winter designation and the 30 is the high temperature designation). It is the viscosity modifier additive that produces a thickening effect at high temperatures but is dormant at low temperatures.

from
Castrol Australia - How To Grade Motor Oil

tjmr2 · 07-11-2008, 01:02 AM

Viscosity modifiers reduce the rate of viscosity change with temperature, by adding polymers and copolymers of olefins, methacrylates, dienes or alkylated styrenes. As the polymers expand with increasing temperature to counteract oil thinning at higher temperatures. (the oil gets thinner while the additives string together into longer chains to give the appearance to your engine of thicker oil.)

As the oil gets older the additive polymers break down and the oil loses it's "Muilti Viscosity" ability.

The science of oil additives isn't at question here, it's if the oil is actually thinner or thicker at start vs twenty minutes later.

My request for an experiment on your part remains the same.
Freeze a bottle of oil overnight and try to pour it out in the morning.
Then leave a bottle out in the sun all day and try pouring it out.

Gairloch · 07-11-2008, 01:24 AM

Mista2 you're still dead wrong. Cold oil is THICKER than warm oil. Lower viscosity number is THINNER than a higher viscosity number. If you don't want to believe it try what tjmr2 suggested and try pouring some oil that's been in a fridge or freezer versus stuff that's heated.

What is the recommended grade oil for that engine? 15W-40 seems to be a pretty thick oil for a toyota engine. Could just be that until you warm up the oil and it thins out some the pump just can't keep up with it.

OldSkool · 07-11-2008, 05:15 PM

Quote:

Originally Posted by Gairloch

What is the recommended grade oil for that engine? 15W-40 seems to be a pretty thick oil for a toyota engine. Could just be that until you warm up the oil and it thins out some the pump just can't keep up with it?

Exactly what I'm thinking in my case. I have 10w-30 now (for the change) and
it will be thinner at all temps. Most 80's cars used 10W 30 as I remember.

alamostation · 07-15-2008, 06:21 AM

This is a great puzzle. Someone should send it in to Car Talk and see what Click and Clack have to say.

In my opinion there is a blockage in the oil pickup screen. I haven't opened up my MR2's engine yet to see what exactly is there, but every engine I've worked on had a screen in or over the intake to the oil pump. If this is clogged, you will have trouble drawing cold thick oil into the oil pump through the blockage. As the engine warms and thins out the oil, it will more easily pass through the blockage and your oil pressure will increase.

My advice would be to drop your oil pan and clean out or replace the oil pickup tube and screen.

I can't think of anything else that would cause the symptoms you described.

tjmr2 · 07-16-2008, 01:54 AM

alamostation, that's not a bad swing of the bat. Just have to wait for oldskool to tell us if his oil change solved the problem or how much deeper he had to go and what the root source cause was.

You might have hit a home run, time will tell.

OldSkool · 07-20-2008, 05:23 PM

Changed the oil pretty much on schedule, and it helped, but still have the
odd pressure chages at times. My buddy who used to work on big trucks of all
kinds mentioned the pickup screen as well, so that is next on my list! Seems
much better than it was, I'll keep everyone posted tho, as I check stuff.

07-07-2008, 06:42 PM	#1 (permalink)
OldSkool Some Skills Join Date: Jun 2008 Location: B-Town, Indiana Posts: 50 Thanks: 8 Thanked 2 Times in 2 Posts My Google Map iTrader Rating: (0/0% )	TIA for suggestions on odd phenomena: Loss of oil pressure until oil warms? For the first 15 minutes or so, (less than 20 for sure) I get lower oil pressure at RPM's above idle. It is nearly bottomed out on the gauge at 3K. When the oil warms up (several minutes after the coolant, makes sense I guess) Oil pressure resumes to normal and stays there even at higher RPM's. (5K+) Is this common and can I do anything to prevent starvation of oil when cold? I just want to know if this is a common "Toy" problem and what you all did. More input after your ideas... LMK!

07-11-2008, 01:02 AM	#15 (permalink)
tjmr2 Cage Fighter Join Date: Jan 2008 Location: Colorado Posts: 410 Thanks: 0 Thanked 62 Times in 59 Posts My Google Map iTrader Rating: (0/0% )	Viscosity modifiers reduce the rate of viscosity change with temperature, by adding polymers and copolymers of olefins, methacrylates, dienes or alkylated styrenes. As the polymers expand with increasing temperature to counteract oil thinning at higher temperatures. (the oil gets thinner while the additives string together into longer chains to give the appearance to your engine of thicker oil.) As the oil gets older the additive polymers break down and the oil loses it's "Muilti Viscosity" ability. The science of oil additives isn't at question here, it's if the oil is actually thinner or thicker at start vs twenty minutes later. My request for an experiment on your part remains the same. Freeze a bottle of oil overnight and try to pour it out in the morning. Then leave a bottle out in the sun all day and try pouring it out. Last edited by tjmr2; 07-11-2008 at 02:18 AM.. Reason: accidently hit post too soon

07-20-2008, 05:23 PM	#20 (permalink)
OldSkool Some Skills Join Date: Jun 2008 Location: B-Town, Indiana Posts: 50 Thanks: 8 Thanked 2 Times in 2 Posts My Google Map iTrader Rating: (0/0% )	More Info: Changed the oil pretty much on schedule, and it helped, but still have the odd pressure chages at times. My buddy who used to work on big trucks of all kinds mentioned the pickup screen as well, so that is next on my list! Seems much better than it was, I'll keep everyone posted tho, as I check stuff.

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07-08-2008, 07:54 AM	#2 (permalink)
Mista 2 Cage Fighter Join Date: Nov 2006 Location: Adelaide, Australia Posts: 463 Thanks: 16 Thanked 21 Times in 21 Posts My Google Map iTrader Rating: (0/0% )	What oil do you have in it at the moment? your oil could just be too thin. This one is a stab in the dark but your oil pump might be on the way out and cant move the thin (cold) oil. are you getting any loud ticking noises or anything else you should add?

07-08-2008, 09:37 AM	#3 (permalink)
mr2magic deutsch type skillz Join Date: Feb 2008 Location: Hannover, Germany Posts: 1,201 Thanks: 107 Thanked 53 Times in 49 Posts My Google Map iTrader Rating: (3/100% )	Correct me if I'm wrong but his oil would get even thinner when warm resulting in even less pressure by your reckoning. When did you last change oil, filter and pump? Could your oil be to thick until warm?

07-08-2008, 07:52 PM	#6 (permalink)
BRoman walking amok Join Date: Jun 2008 Location: TX Posts: 14 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Filter change couldn't hurt...a clogged filter could do this If you're seeing no pressure and no warning light, could be the gauge. Grounding the wire to the sensor should send the gauge to 100%. Just some things to try

07-09-2008, 05:56 AM	#8 (permalink)
Mista 2 Cage Fighter Join Date: Nov 2006 Location: Adelaide, Australia Posts: 463 Thanks: 16 Thanked 21 Times in 21 Posts My Google Map iTrader Rating: (0/0% )	I dont have anything backwards. When the oil is cold and thin it wont build up to he same pressure that warm oil will. You never said the oil pressure at 1,000 RPM. It could just be your oil pressure switch being dicky or because you are using diesal and a reused filter it could have built up crap on it. I would do an oil flush, change the filter and put a magnetic sump plug it. While the oil is out i would have a look at the oil pump if you can. For those that really want to know oil starts off thin so it can get to the moving parts of your engine and if it is a multigrade will thicken up as it get hotter. As for as the viscocity that 4AGE's you can put anything you want in. you will just need to remember that too thin and you wont get the oil pressure that is ideal and too thick and you'll end up burning it off as it get drained into your intake. Why did you not drain the 1.4q to begin with?

07-09-2008, 08:08 AM	#9 (permalink)
mr2magic deutsch type skillz Join Date: Feb 2008 Location: Hannover, Germany Posts: 1,201 Thanks: 107 Thanked 53 Times in 49 Posts My Google Map iTrader Rating: (3/100% )	^Sorry but you are so wrong it hurts! Cold oil is most definately not thinner than warm or hot oil! The viscosity of oil is merely a measure of how much the thickness of the oil changes/decreases with increased temperature! Please be informed before writing something like that.

07-09-2008, 08:20 AM	#10 (permalink)
mr2magic deutsch type skillz Join Date: Feb 2008 Location: Hannover, Germany Posts: 1,201 Thanks: 107 Thanked 53 Times in 49 Posts My Google Map iTrader Rating: (3/100% )	By the way you can almost deduct what I said by looking at the oil weights: 0W - 40 - Viscosity index 0 at Winter temp-40 at operating temp 5W - 40 - Viscosity index 5 at Winter temp-40 at operating temp (Winter temp = 0 °F)

07-10-2008, 01:21 AM	#12 (permalink)
tjmr2 Cage Fighter Join Date: Jan 2008 Location: Colorado Posts: 410 Thanks: 0 Thanked 62 Times in 59 Posts My Google Map iTrader Rating: (0/0% )	Mista 2: Put a bottle of oil in your freezer, leave it set overnight and try to pour it out, then get back to us. Oldskool, You didn't mention that the engine rattled or made bad noises while it shows low pressure so thats the good news, the bad news is according to the Toyota manual aka BGB the following can cause a loss of oil pressure: 1. Oil leakage - nope 2. Relief valve faulty - possible 3. Oil Pump Faulty - possible but unlikely as it pumps thinner oil, telling us the clearances in the pump are ok 4. Poor quality engine oil, don't know what brand you are running so possible but unlikely 5. Crankshaft & or Connecting rod faulty, nope you have pressure when hot not cold, 6. Oil filter clogged, possible hotter thinner oil is flowing thru plugged media that the thick cold oil won't. If the oil pressure gauge didn't move it might be faulty, but since it changes once the car warms up it's probably ok. I'd start with the easy stuff first, change the oil and filter, use a "Toyota" filter from the dealer (no I'm not associated with Toyota in any way except I own one), and a good quality name brand oil. Where you live probably a 10w40 this time of year. The really bad news is if it's an relief valve or oil pump you get to drop the oil pan, remove the inlet, then remove the alternator belt, AC belt, the timing belt, and the front crank pulley before you can remove the oil pump. Good luck, we look forward to hearing your resolution.

07-10-2008, 06:53 PM	#13 (permalink)
OldSkool Some Skills Join Date: Jun 2008 Location: B-Town, Indiana Posts: 50 Thanks: 8 Thanked 2 Times in 2 Posts My Google Map iTrader Rating: (0/0% )	Oops, forgot to say, no odd engine noises at all. If it is a pump, at least I have all the tools. I am somewhat of an engine guru after all I am doing the oil change Friday nite.

07-10-2008, 10:47 PM	#14 (permalink)
Mista 2 Cage Fighter Join Date: Nov 2006 Location: Adelaide, Australia Posts: 463 Thanks: 16 Thanked 21 Times in 21 Posts My Google Map iTrader Rating: (0/0% )	A monograde is an oil whose viscosity is defined at only one temperature, either high or low. A multigrade must meet both high and low temperature viscosity requirements simultaneously. This makes multigrades an easy and popular year-round choice for drivers who experience hot summers and harsh winters. They are easily recognized by the dual viscosity designation (i.e. 10W-30 where the 10W is the low temperature, or winter designation and the 30 is the high temperature designation). It is the viscosity modifier additive that produces a thickening effect at high temperatures but is dormant at low temperatures. from Castrol Australia - How To Grade Motor Oil

07-11-2008, 01:24 AM	#16 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 5,313 Thanks: 139 Thanked 296 Times in 264 Posts Blog Entries: 4 My Google Map iTrader Rating: (7/100% )	Mista2 you're still dead wrong. Cold oil is THICKER than warm oil. Lower viscosity number is THINNER than a higher viscosity number. If you don't want to believe it try what tjmr2 suggested and try pouring some oil that's been in a fridge or freezer versus stuff that's heated. What is the recommended grade oil for that engine? 15W-40 seems to be a pretty thick oil for a toyota engine. Could just be that until you warm up the oil and it thins out some the pump just can't keep up with it.

07-15-2008, 06:21 AM	#18 (permalink)
alamostation Benevelent Mad Scientist Join Date: Apr 2007 Posts: 28 Thanks: 4 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	This is a great puzzle. Someone should send it in to Car Talk and see what Click and Clack have to say. In my opinion there is a blockage in the oil pickup screen. I haven't opened up my MR2's engine yet to see what exactly is there, but every engine I've worked on had a screen in or over the intake to the oil pump. If this is clogged, you will have trouble drawing cold thick oil into the oil pump through the blockage. As the engine warms and thins out the oil, it will more easily pass through the blockage and your oil pressure will increase. My advice would be to drop your oil pan and clean out or replace the oil pickup tube and screen. I can't think of anything else that would cause the symptoms you described.

07-16-2008, 01:54 AM	#19 (permalink)
tjmr2 Cage Fighter Join Date: Jan 2008 Location: Colorado Posts: 410 Thanks: 0 Thanked 62 Times in 59 Posts My Google Map iTrader Rating: (0/0% )	alamostation, that's not a bad swing of the bat. Just have to wait for oldskool to tell us if his oil change solved the problem or how much deeper he had to go and what the root source cause was. You might have hit a home run, time will tell.