So... cruising along, to go pickup the chick and go for a ride.

Cruise control, 75mph, flat fwy. I look down, and notice the coolant temp rising fast, and i notice the oil pressure light is dimly lit (not HARD on). I go OH NO.... and put it in neutral (take any load off the motor and let it idle), and roll to the side of the road. I killed the motor before i let the temp leave the 'optimal range' bracket. (did not hit the H on the scale).

Called my pops, told him to bring some water and meet me (i had driven the car 7 miles from my house, had let it warm up, and then began to drive). I change the oil every 3K miles with Synthetic Castrol, and take good care of my cars.

The car exhibited NO signs of overheating, i put a quarter of a quart of water into the coolant overflow tank, let it sit for about 30 minutes, and tried to gdrive the car 500yds to the next offramp.

Started the car, Idles perfect (no noises, rock steady), no knocking or any other signs indicative of NO OIL PRESSURE.

I pulled out into traffic nice and slow, got about 400 yds before the temp spiked fast. Killed it again and waited for the tow truck.

The rapid coolant spike makes me think the thermostat stuck partially closed.

I have no clue about the oil pressure idiot light.

I have the nissan factory service manuals, and did a diagnostic check on both the oil pressure sender, and the gauge cluster itself to make sure i am not getting false readings. Unfortunately, they all say systems are A-OK.

The motor exhibits no signs of lack of oil pressure. I need to throw a mechanical gauge on it to verify.

I changed the oil when it got home (was due, and planned for today). There is some 'cottage cheese' or water vapor at the filller cap, but there was none present in the oil. (came out brown and solid, like always).

Craig downs and I Started to do a compression check, and believe we have a Harbor freight gauge (was reading 75-100 psi on all cylinders. WAY too low to be legitimate, and the motor runs perfect and still had plenty of power. ).

What are your thoughts. I could believe headgasket, but there should be more water in the oil, if it blew a HG. runs fine, no steam out the exhaust.

i need to do a thorough leak down test, but am scared to run the motor with an indicated low oil pressure.

Your thoughts? Its my daily driver.... i may have to dig out the porsche to get me to school now.

Think intake gasket but not sure how that would affect oil pressure unless there was a signifcant amount of water in the oil.

even after oil change, it INDICATES low oil pressure. Until i stick a mech gauge on there, i dont know if i believe the gauge

are you using one of those "extreme tough guard" or whatever POS fram filters? id suggest to use whatever filter you'd get from the dealer. does the water pump run off the serpentine? is this maybe your problem? maybe is the oil cooler leaking into the coolant system or is the OC separate from the radiator? could it be possible that the water pump and oil pump run off of the timing drive system is the belt shot? haha sorry for possibly answering questions with questions.

If you stick with the 914 you won't have these problems...

ALWAYS used a factory nissan filter. water pump is run off the serp belt yes. OC is seperate.

Belt is fine. No slipping, and the water pump has no play.

Aaron, have you pulled any spark plugs and if so, what did they look like?
How about the thermostat and hoses?
Have you run the engine long enough to let it heat up again?
Mike

All the plugs looked fine. And they were all the same shade of niceness

Im not gonna run the thing until i am certain i have oil pressure.


No sense wrecking a motor, just to find a cooling problem

Gawd... i love the simplicity of aircooled cars LOL

Wise move waiting to verify oil pressure.
Like you said, not worth wrecking the engine.
I had a head gasket go out on a Ford EXP years ago with a similar experience.
Pretty easy to pressure test the cooling system, with the engine off and again while running. After inspecting your thermostat, check the hoses too.
Good luck, Mike

pull the spark plugs, pressureize the cooling system and crank the engine. you'll see water out of the hole(s) where the head gasket/cracked head is. sounds like a small leak though from the small amount of water you indicated you put in and the plugs being evenly good looking.

did it smoke (white) out the tail pipe?

mike

edit: i reread... no steam, my bad. you could have low/no oil pressure. making it run hot??

Aaron..is it the V6? I had a Xterra 2001 with the V6 which had the same thing happen. Turned out it was the head gasket that failed, right up by the firewall...it never blew white smoke, steam or anything..only poor oil pressure and ran extremely hot... could not see it until We noticed a small oil leak. It doesn't leak into the coolant jacket for some strange reason.....

my bet is the head gasket.


Michael

That sounds like a dead ringer for my v6. I havent seen an oil leak yet. I will look closer. I just dont know how the oil pressure would suffer as a result of the car eating a head gasket. Did you have to do a new oil pump?

I will do the work myself, but just curious what it cost you in the end?

A timing belt/waterpump/t-stat kit is sub 300 bucks, wonder what a head gasket/studs/ etc kit will cost

Thanks,

AA

pressure test the cooling system.
It will show you the leak.

The oil pressure goes up when water gets in the sump....more volume...higher pressure. It actually pegs the gauge.

It is probably a blown gasket which is not a big deal really.
Change the belt while you are there...and the water pump.
Look for oil in the coolant...its a beotch to clean out, but we had good luck with the oil out stuff from prestone...

Rich

If your Nissan has an oil pick-up tube screen, check that too.

Sounds like you should drain your coolant to see it the impeller brokeoff the water pump.If it's plastic, theres a good chance you will find some plastic pieces in there...

My non-Nissan experience advise... I had similar on my VW....

Did it really die?

Water vapor out the exhaust?
Blackened coolant?

The temp spiking... Cooling fans coming on? Thermostat stuck? Water pump impeller intact?

Lack of OP might mean blown OC seal. Does your truck have 2 oil coolers? 1 internal and cooled by the coolant, one external?

Aaron,

Is the stock Nissan gasket made from organic material or is it metal? My headgasket blew on my 914's Suby engine and was replaced with Cometic metal laminate gaskets. Maybe you can do the same with your Nissan?

Keith

That sounds like a dead ringer for my v6. I havent seen an oil leak yet. I will look closer. I just dont know how the oil pressure would suffer as a result of the car eating a head gasket. Did you have to do a new oil pump?

I will do the work myself, but just curious what it cost you in the end?

A timing belt/waterpump/t-stat kit is sub 300 bucks, wonder what a head gasket/studs/ etc kit will cost

Thanks,

AA
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It was around $380 in parts, did not replace the pump..but it sure warped the exhaust manifold...the truck ran an additional 20K until my daughter totalled it out

Been insanely busy with work and school lately. Truck gets lovin tomorrow