Oil Level/Comsumption

[GOFAST]

I have a '95 with about 12k miles. I purchased the car about one year ago and have found it difficult to get a consistent oil level reading on the dipstick. My last oil change was about 3k miles ago (Mobil 1 XP 10W30), and I added about 8 2/3 Quarts which read slightly below the full mark on the dipstick. Since the change I have added the remaining 1/3 Quart (9 total), it now reads in the middle between add and full.

The engine has either started to burn oil or I just never got it full from the last change. I would appreciate your input/experience.

Thanks.

[PhillipsLT5]

Wait overnight or 24 hr to check
Let the same amount of time to pass with each check for consistency
These cars will normally use some oil especially with spirited driving

http://www.zr1specialist.com/HAT%20W...5%20Engine.pdf

http://www.zr1specialist.com/HAT%20W...ate%202011.pdf

[gbrtng]

My 91 uses about a quart in 1500-1800 miles on the road. On the track about a quart in 300 miles. Typical from what I have heard.

[mike100]

Originally Posted by gbrtng

My 91 uses about a quart in 1500-1800 miles on the road. On the track about a quart in 300 miles. Typical from what I have heard.

I can concur that that doesn't sound excessive, although I would admit that I was worried about it when i first got the car. The only observation i can share is that the "top" quart burns quickly, but after it is running a quart low, the windage losses seem to be less.

[Hib Halverson]

I don't think you need to wait a day but you do need to wait several hours to get an accurate read of oil level from the dip stick.

An engine using a qt. every 1500-1800 street miles is likely in need of some service...perhaps valve stem seals. That seems like a lot of oil use for an LT5 unless it's very high mileage or maybe using a 5W30 or 5W20.

With my LT5, I've never experienced the "top quart" burning quickly.



My 95, with about 60,000 miles on the motor, uses a quarte in about 8000 miles.

[efnfast]

Hib, do you go 8k between changes? I know oil is important, but it seems many people change it far too often. Wasn't it Jiffy lube that started the 3000 mile oil change? Subject of a new thread?

[tomtom72]

I thought that the 405 hp motors got exh & Int valve stem oil seals? I'm almost positive the 375 hp motors are missing one or both, I think it's only the exh seal they left out?

Anyway, GOFAST how are your PCV valves? I change mine every year as part of my "get ready" for the season. I have noticed that they don't make that clear metallic clinking sound after a season's worth of use, for me somewhere between 6k to 8k miles. As I get towards season's end my oil use goes up or becomes accelerated if you'll allow me that phrase. I can't find the oil on the plugs. Anyway, my point is my LT5's use seems directly related to the health of the PCV valves...or at least that's JMHO thru my own observation. Oh yea, pounding on Her just seems to speed up oil loss no matter when I do it. One of the development issues LOTUS had, ccv blow by ( my words, not LOTUS ), as there is no place for the internal wind with oil in it to slow down enough for the oil to coalesce and fall out of the air stream. Or at least that's what I think they, LOTUS, was saying. I would think that if that is true, then how clean the PCV valves remain over their time in service would be very important to oil loss?

As for checking the oil level. I use my car only on weekends and that's when I check my oil as part of my pre-start up check list. I always get consistent readings from the dipstick. If you think about all the places in our heads that oil can hide I can easily see 4 or 5 hrs should pass before all the oil gets back to the pan. Okay maybe a bit less?

These are just my observations with how my engine behaves in this regard.


Tom

[Paul Workman]

Originally Posted by tomtom72

I thought that the 405 hp motors got exh & Int valve stem oil seals? I'm almost positive the 375 hp motors are missing one or both, I think it's only the exh seal they left out?

Anyway, GOFAST how are your PCV valves? I change mine every year as part of my "get ready" for the season. I have noticed that they don't make that clear metallic clinking sound after a season's worth of use, for me somewhere between 6k to 8k miles. As I get towards season's end my oil use goes up or becomes accelerated if you'll allow me that phrase. I can't find the oil on the plugs. Anyway, my point is my LT5's use seems directly related to the health of the PCV valves...or at least that's JMHO thru my own observation. Oh yea, pounding on Her just seems to speed up oil loss no matter when I do it. One of the development issues LOTUS had, ccv blow by ( my words, not LOTUS ), as there is no place for the internal wind with oil in it to slow down enough for the oil to coalesce and fall out of the air stream. Or at least that's what I think they, LOTUS, was saying. I would think that if that is true, then how clean the PCV valves remain over their time in service would be very important to oil loss?

As for checking the oil level. I use my car only on weekends and that's when I check my oil as part of my pre-start up check list. I always get consistent readings from the dipstick. If you think about all the places in our heads that oil can hide I can easily see 4 or 5 hrs should pass before all the oil gets back to the pan. Okay maybe a bit less?

These are just my observations with how my engine behaves in this regard.


Tom

Hi Tom,

Your're correct, far as the 90s go. They were sans seals on the exhaust valves - per Lotus Engineering felt those valves needed extra lubrication (ref: Heart of the Beast?). I've also read where the particluar open deck architecture employed in the LT5 is prone to some oil consuption, as a result of the top of the sleeves anchored to the head via friction. Sleeve lenght uniformity is absolutely critical to oil consumption, and tollerances being tollerances, and vibrations and stress being what it is (read: sleeve instability), sleeve stability contributes to oil consumption.



Marc's caging the sleeves in his BIG inch builds seems to be addressing at least some of the oil consumption (have to ask 'im or Frank U) by stabilizing the sleeves (reducing the dependance on friction against the head for stability). I've not heard yet if AES' closed deck design is effective in reducing oil consumption, but clearly that design stabilizes the sleeves as well.



(Maybe someone with REAL expertise could chime in? )

Comments about "first quart" consumption was news to me. And too can you or anyone tell me if the hashed segment on the dip stick represents a quart or is it something less? I put in a quart when the level was just below the hash, and checked it the next day. The level now as above the hash (full) line by an equal amount....WTF? I'm wondering if the seal on the dipstick caught on the edge of the tube and maybe didn't allow a proper sounding of the oil level. Have you (or anyone else) ever noticed that??

From the way I drive (spirited ... Hey, living in the country has its advantages!), my consuption has always been a quart and a little more between 5000 mile changes. After getting hot a couple times, and having a coolant disaster once, I'm monitoring it closely for a while to see zackly what it is now. (I have seals on all valves now).

Gotta run!

P.

[scottfab]

Originally Posted by Paul Workman

...snip....

Comments about "first quart" consumption was news to me. And too can you or anyone tell me if the hashed segment on the dip stick represents a quart or is it something less? I put in a quart when the level was just below the hash, and checked it the next day. The level now as above the hash (full) line by an equal amount....WTF? I'm wondering if the seal on the dipstick caught on the edge of the tube and maybe didn't allow a proper sounding of the oil level. Have you (or anyone else) ever noticed that??
...snip..

P.

I have an opportunity to verify this right now. Mine is right at the bottom mark now. I'll add a qt and check it in 8 hrs or so.

[GOLDCYLON]

Originally Posted by Paul Workman

Hi Tom,

Your're correct, far as the 90s go. They were sans seals on the exhaust valves - per Lotus Engineering felt those valves needed extra lubrication (ref: Heart of the Beast?).
P.

Yep Concur the MY 90 had no seals for the exhaust valves. That started MY 91. However, before I replaced my motor it always burned through the first quart real fast. Another question if I may does anybody see a lot of black soot/carbonation on their rear fasica from there exhaust like I used too? GC