: Northstar V8 and 4T80E questions



STSClint
12-31-12, 10:43 AM
I have a couple of questions:

My first is, am I supposed to drive my engine hard? For example, step on the gas and pass people, do WOT twice a month, and take it out on the highway. Or do I drive it like I have been, like a granny (for MPG's, and man does this car get GREAT gas mileage for a V8).

My second question is, should I flush the coolant every 50,000 miles or is it safe to do it every 100,000 miles?

Ranger
12-31-12, 11:17 AM
Highway driving doesn't do much. At 70 MPH it is still loping along at about 2300 RPM. See the "Full Throttle" article in the Technical Archives at the top of the forum page.

Change (not flush) your coolant every 2 years.

LittleNo
12-31-12, 12:02 PM
This makes me smile :D had you ever been to Germany? my 98 STS has now 130k miles on it, it has to do 200 kph (125 mph) every day on the Autobahn, WOT at least twice a day and runs great. OK, I had to do the Head Bolt Time-Sert Job 20k miles ago, but that must not be because of the hard usage since many N* have the same problem in the U.S. too. The transmission is still the first and shifts like new. I change the transmission oil every 15k miles and every 30k miles the upper transmission filter.

Changing the coolant every 2 years is excellent, but every 5 years would be enough, I think.

basscatt
12-31-12, 12:21 PM
I have a couple of questions:

My first is, am I supposed to drive my engine hard? For example, step on the gas and pass people, do WOT twice a month, and take it out on the highway. Or do I drive it like I have been, like a granny (for MPG's, and man does this car get GREAT gas mileage for a V8).

My second question is, should I flush the coolant every 50,000 miles or is it safe to do it every 100,000 miles?
----------------------
am I supposed to drive my engine hard
SUPPOSED TO? - NO - can you? - it won't hurt anything -

Or do I drive it like I have been, like a granny
some will tell you "driving like a granny" is bad for a Northstar motor -
consider how many grannies drive Northstar powered Cadillacs - and never have a problem -

I say drive it NORMALLY - and occasionally - give it a WOT -

should I flush the coolant every 50,000
actually - you should CHANGE - NOT FLUSH - the coolant every 3 years -

Submariner409
12-31-12, 12:32 PM
Heh, heh............. The Northstar is a happy engine at 120. Hard usage (which is VERY different from abuse) is good for the engine and has exactly nothing to do with a possible head gasket problem due to cylinder block head bolt hole thread failure.

The WOT sequence, so often misinterpreted and misused, is a technique used for loading the engine (cylinders, pistons, rings) to their maximum design power output, then unloading the engine by forced high speed deceleration, thus forcing the piston rings to shed carbon - the cause of stuck rings and excessive oil consumption (said consumption not due to worn rings, valve seals/guides, cylinder walls, leaks).

Given its healthy daily use, I'll bet that LittleNo's STS is significantly faster and quieter on acceleration than a city-driven example of the same year/model. It does not need an occasional workout to stay clean and free - it lives that way. His car is the equivalent of a NFL wide receiver as compared to the Miller advertisement couch potato.

(LittleNo, Do you run a 10W-30 or 10W-40 EURO oil in synthetic or conventional ?)

LittleNo
12-31-12, 03:17 PM
Heh, heh............. The Northstar is a happy engine at 120.
yep, it becomes alive above 4000 rpm :D but seriously, it really does a good job compared to the modern Audi and Mercedes stuff on the roads (I mean, it's basically a 20 year old engine). The only thing I miss on European roads is a 6-speed automatic.

I run 5W40 synthetic in all N* over 10 years now. It turned out to be the best compromise for our needs. The difficulties we have here: Many times a trip is not longer than lets say 15 minutes, but within those 15 minutes we need performance. So we often don't have time to carefully warm up the engine before kickin it (of course I do my best, but that's the reality on the roads here). So we need an oil with good performance from the first moment on, even at low temperatures, and on the other side, the oil must handle high temperatures (the N* oil cooler works well at high speeds, but the oil temperatures rises quickly above 200F). The only negative thing I can report about 5W40 is that it tends a bit more to leak from the oil pan gasket and the crankshaft seals. But I can live with that (I simply put in new seals when I had the engine out for the headgasket).

Ranger
12-31-12, 03:28 PM
Unfortunately, we do not get to exercise our engines like that over here (not legally anyway).

maeng9981
01-01-13, 03:42 AM
I wish we had a road where we can travel high speed legally.

LittleNo
01-01-13, 06:37 AM
Well, yes, I understand it can be annoying never to push it without the risk. But you forget, the Autobahn is not a race track, it's a road for travelling purpose, and therefore it has many rules, so driving is not as easy and relaxing as in the U.S. - particularly as in the south, where you have much less traffic on the roads as we have here. When I was in TX for holliday I enjoyed the relaxed driving :-) You will never find anything like this over here.

Ranger
01-01-13, 10:30 AM
I guess everything has it's price as they say.

Submariner409
01-01-13, 10:51 AM
I can second his Autobahn/Texas driving comparisons. When I was stationed in Naples from '67 - '70 we drove the Autostrada from/to Naples - Rome frequently and speeds were 85 - 100 all the way. You keep one constant eye way ahead and the other in the rearview for the Ferrari or Porsche coming up your rear at 130 - a relative closing speed of ~50 mph. Thus the flash-to-pass development. Moving accidents are over a quarter mile long at those speeds - parts everywhere. Drove the Autobahn also, while on leave. A 1965 Chevelle Malibu SS 327/350 was NOT the car to attempt road running at 115 mph. Been there, done that - scared.

A group of cars can safely travel at 110 mph all day long - as long as their relative speeds remain at 0. When one car breaks out, there's hell to pay - but traveling in a pack at that speed demands constant attention: there's no looking for the cup holder. Imagine the typical blonde in a Toyota blasting down the Autobahn at 120, texting and painting her fingernails while sipping her Starbucks. Only in the USA. (Probably not.....)

stoveguyy
01-01-13, 11:13 AM
What is upper trans filter? Under side cover? How do u easily change that? Or is it. OT easy to change?

Submariner409
01-01-13, 04:41 PM
The "upper filter" he mentioned is buried inside the transmission and can be changed during complete teardown and overhaul. Otherwise, the primary screens take care of the "filter" duties.

Transmission fluid does not need a "filter" because there's nothing to contaminate it - unless the transmission parts start to disintegrate and then the screens only delay the inevitable.

Please don't hijack threads.

stoveguyy
01-02-13, 08:29 AM
why did GM put a filter on the 4t65e trans and only a screen on the 4t80e trans? both trans were designed about the same time. maybe by the same department? what type of filter media is in the 4t65e filter? some simple mesh?

Submariner409
01-02-13, 08:55 AM
Mesh. They're all screens. The "fluid filter" is an enclosed (in a flat metal box) fine mesh screen labyrinth inside the side cover. It IS called a "filter" but the media is not our normal synthetic or paper pleated affair like an engine oil filter.

Dug this out of the shop manual............... it takes a GM shop labor rate of 11 hours to replace.

Ranger
01-02-13, 11:17 AM
why did GM put a filter on the 4t65e trans and only a screen on the 4t80e trans? both trans were designed about the same time. maybe by the same department? what type of filter media is in the 4t65e filter? some simple mesh?
Did you mean 4T65E or 4T60E?

EDIT:
Disregard. A little research shows that they are basically the same.

stoveguyy
01-02-13, 11:18 AM
So how easy is that filter to change once trans is out? I can't tell from pic where it is exactly. I assume under side cover? My trans job is done so that filter is not going to be changed anytime soon

Ranger
01-02-13, 11:53 AM
Best I could find is this diagram (hope it works). No parts breakdown, but it appears to be part #010 (upper left), which appears to be in the side cover.
http://www.makcotransmissionparts.com/mm5/graphics/Catalog-pdf/4T80E.pdf

stoveguyy
01-02-13, 12:22 PM
I swapped my trans and debated on changing some things under side cover but decided no. Heck, I had a good used trans for parts. I may have heard that tcc issues are caused by funky converters. Makes u wonder if replacing the converter with a remaned unit is a good idea when using a used trans?

Submariner409
01-02-13, 02:11 PM
Transmission fluid cycles through the torque converter. If the transmission blows up or fails catastrophically, the fluid that was contaminated by the transmission problem will also be in the converter.

STSClint, Sorry that your thread has been hijacked at post #12. If you wish, we can move the transmission questions elsewhere.

LittleNo
01-03-13, 01:31 PM
So how easy is that filter to change once trans is out? I can't tell from pic where it is exactly. I assume under side cover? My trans job is done so that filter is not going to be changed anytime soon
with the transmission out it's easy, just the side cover off and there it is, and side cover with new gasket back on the trans.

Doing it while the transmission is in the car is much more. I lower the whole subframe with the drivetrain to get access to the side cover. I do it in 2-3 hours, but I understand why they claim 11 in the shop manual.

LittleNo
01-10-13, 02:39 AM
I found some pictures of the filter I made while doing the head gasket job:

102194 102195

stoveguyy
01-10-13, 09:44 AM
Subs illustration had the trans turned on end. So filter appeared vertical. To me anyway. I see the last pic shows it is horizontal and on bottom of pan area. I do cad design and am always turning my parts every which way.

Ranger
01-10-13, 10:09 AM
So that's where that SOB is hiding.

Submariner409
01-10-13, 11:53 AM
........... and that's why the thing is changed at transmission overhaul, not with a simple pan drop. I ripped one apart up at Charlie's Transmission a couple of years ago, from a 4T80E that had dropped the fluid pressure pump first stage and lost 1st gear. The crap in the pan and primary screens looked like the surface of the moon - that filter was clean.