Hey guys...

So in my first post, I spoke about the QC Dakota I picked up... with P/O talking about "engine problems" said he wasn't receiving oil pressure... well I grabbed it because it was a beautiful minty truck from the original owner and I hoped a simple oil pressure sensor would do the trick...

So I replaced the switch, topped up the coolant... charged the battery... heres what I have noticed

1) Upon start up... the engine ran smooth, idled around 700 steadily and the oil pressure gauge rose to middle mark... after letting it idle and warm up... the thing dropped to low... and zero (check gauges light went on)... and then went back to middle. During this sweep on the gauge, the engine did not ping, knock... change in idle... sounds the same... no audible knocking sounds or metal on metal etc... sounds like a fine running engine.

If this irregular sweep is happening, where do I look next? Oil switch? The one wire lead to the sensor looked clean, I cleaned it anyway and put some die-electric grease on it.

Your expertise would be much appreciated!

2) When I took off the rad cap, I noticed there was no coolant... so I topped it up and then started the truck, put it on hot and waited for it to warm up... it did, but there doesn't seem to be any coolant in the overflow tank... meaning, when I pull that stick up, its not even registering... if I am getting hot air in the cab and the water temperature is registering, can I assume my thermostat is opening? *** I did not run the truck for long since the gauge above was going loopy... so maybe I need to run it for longer?

Cheers everyone,
Parker

 

1. Put a mechanical gauge on it, temporarily. See what the pressure actually is. You could have a wiring or cluster problem.
2. You topped it up where? The truck will draw off the coolant reserve/overflow reservoir when cold and send fluid back to the reservoir when hot - assuming your radiator cap and the hose are in good condition.

No on the thermostat, it won't tell you anything about it's condition. The thermostat regulates flow through the radiator not the heater core. Coolant always flows through the heater core.

 

1) I'll put a mechanical gauge on it tomorrow and check it out... if it turns out to be fine, I guess I'll have to trace back the wires and see if there is anything foul behind the cluster?

2)I topped it off where the metal rad cap comes off the hose... and let it cycle. Should I be topping off in the reservoir? I am assuming if its full, coolant will leave via that little overflow spigot?

3) NEW: Looked at the fuse panel under the hood... missing an O2 sensor relay and a fuse for power steering... not sure if that is specific to vehicle and model... or if I am legitimately missing a relay... might explain why my bod scanner is flashing O2 sensor fault.... or maybe they took it out because my cat is bad... who knows... whats your take?

 

1, The oil pressure signal comes from the PCM over the computer bus. The cluster is a computer too. So, it may/may not be a wiring problem.
2. You add to the reservoir not under the cap. It should be labeled "full hot".
3. Make/model/emission spec dependent. Which sensor is the reported fault?

 

Did you replace the oil?

I would dump the oil and inspect it see if its sludgy old oil then put in a good quality cleaning oil and filter.

The problem may go away

 

Thanks for your help thus far... I've recorded a video of the gauge so I'll have it up on youtube

1) Will see if I can get my hands on a mechanical gauge to test... SIDE NOTE... no oil came spurting out when I removed the oil sensor as other posts suggested that I read... is that troublesome? The truck had been sitting for 4 months...

As a cheaper alternative, should I change the oil and filter whilst I am at it... may be an easy root of all problems?

2)Ok, I will add to the reservoir and go from there... as it stands, its bone dry... probably another issue but I can't see any signs of leaking or coolant in the oil or oil in the coolant... I'll do a strip test tonight to make sure

3) its a canadian truck, just read somewhere else the relay is used for California and some northeast states... not sure about the power steering fuse though..

 

You beat me to it ... what would you consider to be a cleaning oil? synthetic?

 

most quality oils are cleaning oils now days but synthetic oil is better at it

 

Ok guys...

I changed the oil 5w30 synthetic and a Mobil 1 301 filter... its a bit bigger than the shortie but many of the threads on here seem to swear by the bigger filter... along with wix and napa etc so I know thats a rabbit hole...

Oil was dark brown but no sludge

I also topped up the coolant via the reservoir.

I am sad and frustrated to report that the truck seems to be running rougher and much louder than before the oil change

At the moment, there is a knocking noise coming from the top of the motor, but it sounds like plastic... like a plastic fan would sound if it started rubbing... The gauge still fluctuates...

Not too sure where to go from here... I guess I'll let it settle and return tomorrow.

Would this bigger filter be a poor choice at this juncture.. should I try the 204 that was listed?

 

Let the new oil clean things up a for a week then let us know if things have improved it cant clean ASAP so give it some time.

A thinner oil will make it sound louder at first also just wait