LS1ne

iTrader: (6)

Ok the situation, the engine temp seems to increase the hotter the day is and the longer i drive it. Well duh , yah i know common, NO, when i accelerate say up to 70ish the temp will sometimes climb to a bout 240, sometimes kicking the check gage light on. If i decelerate, say to about 60 it will also drop with the rpm. Being that the gauge is reading hot it kicks my low fans on until the gauge level lowers in temp. Faulty gauge? bad sensor? I can pop the hood after this occurs and place my hand on the intake-warm, check the radiator-full, and well pretty much tell it's Not actually overheating. Ive yet to replace the t-stat but have a new one going in soon. Its mind boggling. btw this usually only gets that high on the highway, in the city no more than 210*

The oil psi gauge also begins to act funny. When hot it will bounce and seem real low like around 20 is that normal?
Also, after running the car you can smell an oil residue smell from the motor, what could i be looking @? valve covers, pcv leakage, any ideas? Thanks

LS1ne

iTrader: (6)

anyone?

wssix99

iTrader: (5)

Sounds like a sticky t-stat. Maybe RPMs are causing pressure changes, which are helping the valve open/shut. Either way, the t-stat should regulate temperature in these situations if all else is well.

LS1ne

iTrader: (6)

thanks for the input, dropping a new t-stat today so im crossing my fingers.
Any other ideas?

also any thoughts on the oil situation?

wssix99

iTrader: (5)

Change your oil ASAP and make sure you don't have a sludge problem. I'd also suggest sending a sample away for an oil analysis. (That may tell you something about the quality of your oil and if any problems are present inside the engine.)

What weight of oil are you running and how long between changes?

LS1ne

iTrader: (6)

mobil 1 10w30 full synthetic spilling over 100K on the speedo..I change the oil every 2.5/3 months

I replaced the thermostat and seems to have cured the problem as far as the temp issue, the old t-stat was prob the stock t-stat considering the condition. Thank you

Should i be using a different oil weight? or oil brand?

wssix99

iTrader: (5)

Brand, no. Weight, yes! Check out your owners manual. For colder months, we need to run 5W-30. If you live in Texas, you could do 10W30 in the summer but given your pressure issue; I'd go to 5W30 or even 0W30 all year around. (Look for Patman's posts on this site for info on 0W30.) If you have a sludge problem, etc., the 5W30 should flow better for you before the engine comes up to temperature.

1 FMF

iTrader: (1)

from your description, it sounds like it is actually overheating and the oil pressure gauge is backing that up. When the engine gets hot, so does the oil and the hotter the oil gets the thinner it gets resulting in a lower pressure reading. This would be most apparent at idle when rpms are very low so the oil pump is not pumping a whole lot, the reduced oil viscosity will result in less oil pressure, and on mine I have been in stop & go traffic in the summer when I used to use 5w30 oil and the radiator fans would kick on telling me the engine is hot and I could see the oil pressure gauge fluttering slightly at 20 psi at 800 rpm... but get the rpms up to 1500 or better and it's solid at 40 psi. So I would say for you this is normal, I would recommend running a 10w40 or 15w40 oil instead of 5w30 in your location, I've been running delvac 15w40 here for the past few years but i only use mine from may to november. if you're not seeing cold weather below 30-40F then there's no reason to use 30 weight other than for fuel economy. The most important aspect of a lubricating fluid is viscosity! I doubt you have a sludge problem, that gets so blown out of proportion from 1 or 2 pics on the internet, as soon as somebody sees any kind of abnormality they think sludge problem. All those bullshit castrol commercials brainwashing people probably has something to do with it as well.

Check and make sure your air dam under the radiator is there so it's scooping air when at speed. With engine running at fast idle squeeze upper radiator hose and feel for surging, this will give an indication that the water pump is pumping. If you can collapse the hose easily with your hand then that's a good sign you have a bad pump, but also make sure the system holds pressure. Might want to try a new radiator cap they are cheap, also make sure the front of your radiator is clean.