Q: Losing coolant, high idle rpm, 2x P0300 1x P1111

asked by on September 30, 2016

Hello, I've been having some trials with my '05 Sentra SE-R Spec V lately. My idle rpm has been fluctuating between roughly 700 and 1600 revolutions per minute, and the car is quite loud. More importantly, I'm losing a lot of coolant from my reservoir with no visible leaks. I am suspecting a head gasket or intake manifold gasket. The hard part is figuring out exactly which one and if my rpm problems are related or not. My oil and coolant are not mixing and the misfire occurs on startup, particularly with a hot engine.

I do not have any equipment to pressure test the cooling system and am lost on where to turn. I'd like to figure out exactly what is wrong with it and what options I have available. Do you have any advice or tips?

My car has 194000 miles.
My car has a manual transmission.

Idle Control Valve Replacement $162.54 - $1028.01 Get a Quote

Hello. From what you describe it would appear that there may be more than one issue with the vehicle. The rpm fluctuations can be caused many different things. A few things I would check are the idle air control valve, and the any vacuum lines for the possibility of a vacuum leak. Coolant loss with no visible leaks can be difficult to diagnose. It may be possible for you to rent a cooling system pressure test kit from an auto parts store, sometimes even free of charge. A cooling system pressure test would be best way to determine if there is any internal, or external oil leaks.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

What do the Maintenance Minder messages mean?
Your car’s Maintenance Minder™ system is designed as a reminder system and a tracker for your vehicle service. It can display a number of different messages in conjunction with the oil life percentage and the wrench symbol on the dash...
Car won't charge
Hello! Since you have replaced the battery, we will put that to the side, but we cannot ignore it. A failed charging system puts a large load on a battery and can damage a new one, so I suggest having...
Rattling Noise coming from the Fan behind the radiator
The cooling fan clutch failure is a common problem with the B5 chassis A4 and VW Passat. When replacing the fan clutch, inspect the fan blade for any cracks as well. If any area of the blade looks suspect, replace...
My car will start, just not run.
Hi, thanks for writing in. I would start with testing your battery and alternator with a multi meter. Good batteries (https://www.yourmechanic.com/article/how-to-buy-a-good-quality-car-battery) hold a charge of 12.6 volts or higher. If the battery is low, try to jump start it. If...
It stalls while driving, fuel pump has been replaced, checked fuel module...still stalls in middle of road
There are a huge amount of possible causes for your stalling problem (https://www.yourmechanic.com/services/car-is-stalling-inspection). They include other fuel related components, ignition (spark) components, electrical components, or air intake components. Do you know for a fact your technician scanned the computer for...
I have added power steering fluid to my car...I have seen a video which says the fluid should be in middle level. Can I add more? 2005 Honda Accord
Hello - either the side of the fluid reservoir will have Max/Min marks for the maximum and minimum fluid level desirable for power steering fluid, or there will be a "dipstick" indicator on the inside of the fluid cap that...
I have a 2004 lincoln aviator and it has a park assist mode on it and i need to know how to deactivate it permanently because it k
You should be able to go into the settings and set it to disable. If you cannot find the settings menu then look in the owners manual to follow the deactivate settings.
Why did my tachometer light and check engine light go on at same time?
You will need to have the computer scanned to get the stored codes. You may have a bad sensor.

Related articles

A Buyer’s Guide to the 2012 Nissan Rogue
While While the Honda CR-V and the Toyota RAV4 generally get the most attention in the crossover utility vehicle (CUV) class, buyers should take a look at the 2012 Nissan Rogue. The second-smallest model in Nissan’s line of SUVs and...
The Best Used Cars to Buy If You’re an Electrician
As As an electrician, you have to haul around wiring, tools and equipment, and tons of supplies. You can’t get by with a small used car, or even a big one. What you probably need is a good used cargo...
How to Monitor Your RPM Gauge to Get the Best Performance Out of Your Car
A car tachometer, or RPM gauge, shows the speed the engine is spinning. Watch your RPM gauge to improve your car's performance and fuel efficiency.