Low oil pressure gauge at Idle make engine coolant hot

[Grizzlyghost]

Hey guys,

 

It been few years now maintaining it... I have 2005 sierra 1500 z71 5.3L extended cab... I gotten it at 80,000 and now it at 182k, i have since replaced the alternator, water pump, coolant hose, flush the tranmission fluids, and now i noticed now it be getting hot while im idling and the oil pressure gauge will be low but when i am driving the oil pressure gauge goes back to middle and the coolant temp will go back to the middle instead being hot... it happen when im going through a stop like a traffic jam... it wouldnt last 5min without getting low oil pressure(although no alarm light) and high engine coolant temp (coolant warning light came on) reaching... i been racking my brain trying to figure it out what could it be... it same thing all over again, driving normal then come to a stop, a long stop then my oil pressure will dip low and then engine coolant will dip pass the 210 mark and get hot til if i am idle long enough it will flash coolant light on... i open the hood check the engine, hoses, coolant level is good, fan blowing, but still getting hot with no leaks or steams... i really love my truck i really need to resolve this asap... pls help???

 

 

G30

[muddkatt]

How long has it been since you replaced the water pump and hoses?

[Dnt]

I am thinking that a 2005 still had a real fan? If so I would replace the fan clutch and give the radiator and condenser fins a good cleaning. 12 years of trash/bugs build up on the heat Exchanger fins needs to be cleaned and 182k on a fan clutch usually results in a weak clutch not engaging fully.

[Grizzlyghost]

How long has it been since you replaced the water pump and hoses?

1 year at least... it did it before then they replaced it under warranty...

[Grizzlyghost]

I am thinking that a 2005 still had a real fan? If so I would replace the fan clutch and give the radiator and condenser fins a good cleaning. 12 years of trash/bugs build up on the heat Exchanger fins needs to be cleaned and 182k on a fan clutch usually results in a weak clutch not engaging fully.

i was thinking about the fan clutch and i had check both fans still come on blowing and there two setting for the fan to blow hi and low... not sure if the fan clutch would make it blow better per se..

[muddkatt]

The fan clutch that Darryl is referring to is the old style mechanical fan that is ran off of a belt and is mounted to the water pump. If your truck has electric fans, then you will not have a fan clutch.

I ask about the pump and hose replacement because you could have air in the system and it would need to be burped or purged to remove all the air.

[Podor]

Are you losing coolant?

[Coby7]

Oil pressure will drop if engine gets hot so this is normal. What isn't normal is engine overheating at idle, my guess is the thermostat may not be opening enough or sticking. When was it changed last?

[SunShine01]

I am thinking that a 2005 still had a real fan? If so I would replace the fan clutch and give the radiator and condenser fins a good cleaning. 12 years of trash/bugs build up on the heat Exchanger fins needs to be cleaned and 182k on a fan clutch usually results in a weak clutch not engaging fully.

This

 

I thought and have had fan clutch issues.

 

One other note. I own a 2005 Tahoe Z71. My dashboard cluster was giving me bad readings of various sorts. Be sure it's accurate too. I replaced my cluster, $450. Much better since !

 

 

Sent from my iPhone using Tapatalk

[dsr611]

This

 

I thought and have had fan clutch issues.

 

One other note. I own a 2005 Tahoe Z71. My dashboard cluster was giving me bad readings of various sorts. Be sure it's accurate too. I replaced my cluster, $450. Much better since !

 

 

Sent from my iPhone using Tapatalk

Too late now, but you could have had the cluster rebuilt using newer, updated stepper motors and new LED lighting for a LOT less than $450 (most places are now around the $100 mark)

[SunShine01]

Too late now, but you could have had the cluster rebuilt using newer, updated stepper motors and new LED lighting for a LOT less than $450 (most places are now around the $100 mark)

Yes but I had an x-tended warranty and I paid the $100 deductible plus some other BS charges they stay up nights figuring how to double dip you and I got Genuine GM parts. I've always been a fan of factory parts for my everyday vehicle. When I wholesaled cars, cheapest fix ruled. Lol

 

 

Sent from my iPhone using Tapatalk

[Grizzlyghost]

The fan clutch that Darryl is referring to is the old style mechanical fan that is ran off of a belt and is mounted to the water pump. If your truck has electric fans, then you will not have a fan clutch.

I ask about the pump and hose replacement because you could have air in the system and it would need to be burped or purged to remove all the air.

 

 

so yeah i have electric fans not the belt driven fans... so when i had the pump and hose replaced im sure they bleed the air out of the system and now recently just to be sure i had the coolant flush and fill again and they bleed the air out for good this time... when i got the truck back it was still getting a bit hot... if the gauge working going back to normal while driving, could it be the oil pump that not pumping while idle...?

 

 

 

[Grizzlyghost]

Are you losing coolant?

 

no im not losing coolant, i check all the hoses and leaks and steams and i just had the coolant drain and refill and replace the radiator cap so...

[Grizzlyghost]

Oil pressure will drop if engine gets hot so this is normal. What isn't normal is engine overheating at idle, my guess is the thermostat may not be opening enough or sticking. When was it changed last?

 

i had the thermostat changed same time as the water pump maybe a year ago or so...

[Grizzlyghost]

This

 

I thought and have had fan clutch issues.

 

One other note. I own a 2005 Tahoe Z71. My dashboard cluster was giving me bad readings of various sorts. Be sure it's accurate too. I replaced my cluster, $450. Much better since !

 

 

Sent from my iPhone using Tapatalk

i had the cluster replace when i first got the truck it wasnt reading the rpm right but now 182k later oil pressure gauge is reading low at idle sometime low pressure come on sometime it read low at idle...