****VH45DE OVERHEAT DURATION****

[i-Zer0]

I think it was in the mid 90's that Cadillac that boasted their 4.9L that could run 'dry' [whether oil or coolant - I forget] for a period of time w/o significant damage - slightly different mechanicals that allowed theirs to do that, I realize - enter, our VH45DE now - - - - - - Was driving down the I-10 fwy in Phoenix on Sunday evening - it's about 105 outside - a/c on - cruise: 65mph, etc - no probs - - happened to glance down @ temp gauge - it was way up past the 'H' - I immediately got off @ an exit ramp [approx 1/4 mile from discovery] - engine began losing pwr and dieselling very badly - when I got to the stoplight, the engine finally shut itself off - cranked, but would not restart - waited a couple of mins - coolant was gurgling in the expansion reservoir - looked @ oil level - bone dry - now I had just chgd the oil last wk - where did it all go - car has not smoked at all - that I ever noticed anyway - and I would have noticed - -anyway, refilled w/ fresh oil - engine finally started after a couple of rough tries but the lifters were then ticking something awful for quite a while - there was a little smoke coming from the exhuast but nothing to really panic about - now, this engine usually does not burn oil but it must have been so hot that the residual on the moving parts was finally burning away through the exhuast - anyway, eventually the ticking went away and the engine sounded fine after that - however the temp level was still riding high - reservoir was refilled again [took about 1/2 gallon of water BTW] - started up again - gauge showed a little over the half-way position [normally it's just below the half-way position] - drove car about 1/4 mile - gauge shot way up again - sounds like a t-stat needing replacement - I am also suspecting that the valve stem seals are the culprit to this whole fiasco in the first place - my theory is that all the oil leaked past them causing a gross overheat condition in conjuction w/ a gummed up t-stat - what impresses me, though, is how this engine can run w/ very little smoking or seizing up from running so dry and no real indications of internal damage [I.E. head gasket/bearings.etc] after what I had just unknowingly put it through on the fwy - true, I didn't drive it very far when I discovered the problem - I guess there must have been enough residual in the moving parts of the engine even though there was hardly any in the pan - how is it that no messages ever came up or no warning lights ever came on - that's what I don't understand - maybe they would have come on or said something in the little screen when the engine would been damaged to the point that I would not just have to replace some little seals and a t-stat - that would have been bad - has anyone ever had a similar experience - am I going to need to add a quart of oil everytime I get gas until I get those seals replaced - if that's really what I would have to do, it's hell of alot better than having to replace the whole engine itself - I can get a new in-crate one from around here for $800, but I don't feel like doing all of that work if I don't necessarily have to - but for the VH45DE to survive this kind of ordeal with no serious damage, I find truly remarkable - - - - - - - BTW it's a 93 w/ 175k miles approx and still running/looking relatively decent - both car and engine/trans - advise - advise - advise - - - - - - - - - - - - - - - - - - -
Modified by i-Zer0 at 10:28 AM 7/3/2006

[elwesso]

Yikes... overheated 2 times.. bad news......

Replace the Tstat and water pump and hope for the best... Assume that the engine could be toast much sooner than expected.

[i-Zer0]

tell me more - go on....

[Q45tech]

Owner ABUSE, trying to blame the valve stem seals ..[tisk,tisk]..........sure....... never seen a problem [Viton seals] unless the oil wasn't change regularly per the 90 day recommendation.

Failure to do the preflight checking! Gas, Oil, Coolant, ATF ........check!

I remember that last serious Q over heat...........we warned the owner his water pump was leaking [BAD] in writing and in front of 2 witnesses. He said he would come back next week.........sure.

He called back within 30 minutes on the side of Interstate, we told him to call a flat bed wrecker and tow it back instead he comes back in a cloud of steam and blue smoke I measured the cylinder heads they were over 470F [well done]. I was afraid to turn it off so we added 4 quarts of oil and sprayed lightly with a hose for 15 minutes...............it never ran again.

He tried to sue us because we didn't warn him [enough] that an overheat could destroy his engine and "even if we did warn him" we let him leave and didn't refuse to let him have his car"........ Sir you are driving an expensive high performance engine not a generic iron block POS.

Every year we get at least one similar situation some survive some don't.

[i-Zer0]

Owner ABUSE, trying to blame the valve stem seals ..[tisk,tisk]..........sure....... never seen a problem [Viton seals] unless the oil wasn't change regularly per the 90 day recommendation.

Failure to do the preflight checking! Gas, Oil, Coolant, ATF ........check!

I remember that last serious Q over heat...........we warned the owner his water pump was leaking [BAD] in writing and in front of 2 witnesses. He said he would come back next week.........sure.

He called back within 30 minutes on the side of Interstate, we told him to call a flat bed wrecker and tow it back instead he comes back in a cloud of steam and blue smoke I measured the cylinder heads they were over 470F [well done]. I was afraid to turn it off so we added 4 quarts of oil and sprayed lightly with a hose for 15 minutes...............it never ran again.

He tried to sue us because we didn't warn him [enough] that an overheat could destroy his engine and "even if we did warn him" we let him leave and didn't refuse to let him have his car"........ Sir you are driving an expensive high performance engine not a generic iron block POS.

Every year we get at least one similar situation some survive some don't.

I do understand what you're saying - now I bought this car last Aug 1st from the prev owner @ 163K miles - they had had things done to it in the year and a half they owned/drove it - not really much of staying on top of everything though, admittedly - now he did religiously chg the oil though - that much I do know - as I said, the engine overall seems okay - hopefully, it's got more of a forgiving nature than some of the ones you have described in your experiences w/ cust's past - now I have 'nursed' this car and have put 12k miles on it in the past year - run it on only 91oct - use magnets - clean underneath the engine oil pan, etc - clean electrical contacts, etc,etc,etc - all was fine until... - if it wasn't for the gauge indicator, who knows - like I said, I just happened to look down - I am getting ready to get this $20 t-stat and chg the oil again - this VH45DE will survive - I hope I have given it enough of a will to continue living - even if it doesn't I am not giving up on the car yet - it's just a car (that I happen to like) - - - - - - - - -

[Jeff Williams]

Overheating is the worst thing that can be done to a highly sophisticated engine. Aluminum and iron do much different things at high temps. Rings go, piston seize, bearings slip and gouge. A lot of really bad things happen. Not to mention, the knock sensors, and other wiring that becomes brittle and weak.

Definitely flush the coolant system and make sure your coolent % is correct. Buy an Infiniti thermostat (not Autozone). You might need a water pump. Chances are your belts and hoses are toasty, and might need replacement too. The oil is definitley cooked, and useless. Change it completely, along with the filter.

I bet your transmission fluid got perty hot as well, since the radiator works as a transmission fluid warmer/cooler. I would replace it as well.

[qship96]

how could valve stem seals allow 6.5 quarts of oil past them in 1 week{your last oil change} without your exhaust blowing enough smoke to confuse the Q with a mosquito fogger? doubt valve seals are to blame on this level of oil use.{maybe tech forgot to replace oil period after draining it} - or,leaking from drain plug/filter.

[Jesda]

The later Northstar 4.6 had the ability to run on just four cylinders in emergency limp home mode. Fifty miles was the promise for driving it without damage.

"If the PCM senses an overheating condition, it temporarily disables up to half of the cylinders. This pumps enough air though the engine to keep temperatures from getting hot enough to cause any damage. Even so, GM says the vehicle should not be driven more than 50 miles in the limp-home mode."

[i-Zer0]

how could valve stem seals allow 6.5 quarts of oil past them in 1 week{your last oil change} without your exhaust blowing enough smoke to confuse the Q with a mosquito fogger? doubt valve seals are to blame on this level of oil use.{maybe tech forgot to replace oil period after draining it} - or,leaking from drain plug/filter.

my point exactly

[paranoidjack]

Owner ABUSEEvery year we get at least one similar situation some survive some don't.

hahahah...sounds like an ER doctor describing a fairly rare patient!

[i-Zer0]

***ALL SEEMS WELL NOW, GUYS - THX FOR EACH OF YOUR INPUTS***finally drove the car home tonight from its stranded loc after some extensive HWY/STOP&GO driving/testing following a quick chgout of the t'stat - car runs w/ the gauge needle just below halfway mark, which I consider normal - engine has the pep it's always had - oil lvl is still where I left it after completely refilling it the night before - not much in the way of noticeable smoke, anyway, that I can see (considering it's 102 and a little breezy here in the SW this eve - the only thing I notice different is a slight whirring sound when I gun it a little - I don't know if it's the timing chains or one of the idler pulleys (I've needed to replace at least one that I know of - been putting it off for other priorities {f/p, batt, alt, etc.}) - I'm not too terribly sweatin bullets over it tho' - and I will address the vlv/slz issue right away - otherwise I feel pretty fortunate - perhaps I will get another thirty to one hundred k more miles, (Ya-rite-heh-heh) this side of either a new engine/transmission or replacement G50 - we'll see - meanwhile, WML - I seem to have had it good so far - I love this place - thx for the support anyway - keep you posted - - - - - - - - - -

[Jesda]

Thank goodness!

You installed a Nissan thermostat, right?

[i-Zer0]

The later Northstar 4.6 had the ability to run on just four cylinders in emergency limp home mode. Fifty miles was the promise for driving it without damage.

"If the PCM senses an overheating condition, it temporarily disables up to half of the cylinders. This pumps enough air though the engine to keep temperatures from getting hot enough to cause any damage. Even so, GM says the vehicle should not be driven more than 50 miles in the limp-home mode."

KUDO'S CADDY - BUT THE G50 SEEMED TO 'SENSE' NOTHING! [OTHER THAN A 'CASUAL' gauge READING] WHY - did the system really 'feel' it wasn't a 'life-threatening issue yet? - if so that's wonderful - if not, then something's sleeping on the j-o-b - - - - - -

[i-Zer0]

Thank goodness!

You installed a Nissan thermostat, right?

my friend - let me tell you something - I have never paid twenty dollars for a t-stat before - for that price, I am assuming it's either a Nissan OEM or 'better' - I have issues w/ non-oem stuff [outside of oil filters, light bulb replacements and TR3 Resin Glaze] from 'Kmart type' auto part stores - this is not a seventy-two Oldsmobile - I get all my 'stuff' for this vehicle from BAP auto parts - most of their inventory comes from the same suppliers Nissan, VW, Toyota, Jaguar, Subaru and others get theirs - at a very reasonable price over dlr pts dept (unless, of course you're good 'friends' w/ the VW pts mgr) - only the best, in my book when it comes to this car of mine - BTW FYI, it's: http://www.bapimportparts.com/ - just chk it out - - - - - - - - - - - - - - -

Modified by i-Zer0 at 10:48 PM 7/3/2006
Modified by i-Zer0 at 10:52 PM 7/3/2006

[Q45denver]

I don't think I would put any undue stress on it or take it on any long trips. Probably a time bomb ready to blow.

[i-Zer0]

Well, if it truly does (which I won't completely rule out, but isn't impossible), I am armed and ready - - - - - - - - - -

[i-Zer0]

Turns out that most of the oil leaked out of the pan due to a pinhole leak in the pan itself - at first I thought it was the pan gasket as I had traced the leak(s) from where they appeared to originate there - so I initially re-torqued the bolts (that I had access to) - the leaks ceased in those areas - I considered the option of utilizing PopPop's instructions in thread No. 165344 to completely replace the pan, if not just the gasket - only prob w/ that is I don't have access to a replacement right now - so I am doing the following:* completely drain the pan* run a couple of pints of diesel fuel through to carry out any trace contamination in the bottom of it so that it's relatively clean* SLOWLY drill a 7/32 hole in the area of the pinhole (to keep the metal shavings to a minimum)* flush another couple of pints of d/f through to carry out any shavings* use a self tapping sht mtl screw w/ its threads coated w/ JB Weld and tap the hole w/ it* allow to cure for a couple of hours* refill the panDONEfortunately, there was still at least a quart or more in the pan when this whole problem was subsequently discovered last Sunday - the engine still runs very well now - but I still need to correct this other situation and here's just a little thinking outside the box - this is my temporary/ permanent fix until I choose to get it done right, a little later (five-hundred bucks for a new pan is not exactly the first priority on a thirteen-year-old car w/ 173K miles on it) - has anyone else ever had similar experiences - [by the way Ty, your inst's for shortcut pan replacement are excellent] - - - - - - - -
Modified by i-Zer0 at 4:02 PM 7/9/2006

[Jeff Williams]

Make sure that whirring noise is not your clutch fan going out. You should be able to spin the fan by hand with the engine off. If it feels stiff, or doesn't spin fairly easily, buy a new one. Once it locks up, it becomes screamer over 2200 RPM.

[i-Zer0]

Make sure that whirring noise is not your clutch fan going out. You should be able to spin the fan by hand with the engine off. If it feels stiff, or doesn't spin fairly easily, buy a new one. Once it locks up, it becomes screamer over 2200 RPM.

You're telling me that when the G50's fan goes out, it does the opposite of what conventional clutch fans do - instead of being loosey-goosey, it stiffens up, becoming a direct-shaft drive which would rob pwr - correct? - I never had or have a problem w/ the fan assy - - - - -