Q: This is Luis from Mesa, AZ. I have a 2000 Maxima. Temp gauge rises when coolant level is normal, but when level drops, gauge reads

asked by on February 11, 2017

When radiator is topped off, and reservoir is to max level, temp gauge rises over time, unless heater is on full blast. However there seems to be a leak, and when coolant level drops after about 3 days or so, temp gauge drops to normal again. So I'm wondering if a damaged coolant temperature sensor needs replacement. And regarding leak, when engine is cold or just hasn't been running after about an hour, white smoke comes from exhaust for about 10 seconds then disappears. Havent pressure testet radiator yet for leaks, but can this be a sign of possible internal leak? Engine oil shows no signs of coolant, and engine runs in great condition (168K miles). OBD does NOT give me any p0300 codes for misfires at all, though I made the mistake of running engine with aftermarket ignition coils for about 5 months, which triggered p1320 code before replacing with OEM coils. Thanks for your help.

My car has 168000 miles.
My car has an automatic transmission.

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

Rough idling during cold starts
The vehicle will have to have the throttle body (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-throttle-body) and idle air control valve (https://www.yourmechanic.com/article/how-to-clean-an-idle-air-control-valve-by-joyce-morse) checked to see if it needs to be cleaned. Also, the engine will need to be checked for any vacuum leaks (https://www.yourmechanic.com/article/is-it-safe-to-drive-with-a-vacuum-leak) when the...
Sudden drop in gas mileage
There are multiple factors that can affect your gas mileage (https://www.yourmechanic.com/article/how-to-easily-increase-your-gas-mileage-by-jason-unrau). Some of these factors would include: how clean the air filter is, how well fuel can flow through the fuel filter. If the fuel filter is doing its job,...
does the 2004 dakota 3.7 liter v6 engine require a clutchfan and the electrical fan also
Your Dakota should have both a mechanical fan with a clutch, and an electric fan. The mechanical fan is the main cooling fan, and the electric fan is designed to come on to supplement the mechanical fan, only if it's...
Gas Pedal is very hard at beginning and RPMs drop.
If the throttle assembly has a cable that attaches the pedal to the throttle valve, the cable must be inspected to see if it is binding within the insulation. Excessive carbon build-up may cause the throttle plate to stick (https://www.yourmechanic.com/services/clean-throttle-body),...
Car shuts off at idle
Hi, thanks for writing in. This is a sign of a failing idle air control valve (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-idle-control-valve). This is a unit that regulates the air flow into the engine as it is mixed with fuel prior to being injected into...
Oil light comes on when braking
You should first check to make sure the oil level is full. If system is full of oil then you should have the oil pressure checked to see if it is in specifications. The problem sounds like when you are...
Engine stalls sometimes but not all the time
Hello, Unfortunately, without additional information as to the make, model and year of your motorcycle it may not be possible to suggest what may be causing it to stall. Depending on whether or not it is fuel injected, or not...
2006 Pontiac GTO - Trouble codes P0300 and P0496. Feels like misfire and/or out of fuel
Hi There, Code P0496 relates to the EVAP system, specifically indicating that the system has detected more flow than normal during a non-purge condition. This means that the system may be trying to purge excess pressure or fumes form the...
I drive Mkvi gti, oil pressure fault at high revs >3k rpm
Although your problem with the oil pressure warning is probably instrumentation. It's a bad idea to ignore oil pressure warnings. If the oil pressure is actually low, it will do serious engine damage very quickly. The thing to do is...

Related articles

The Best Used Cars to Buy If You Live in a Hilly Area
Do Do you live in terrain that is hilly? Do your city streets feature plenty of inclines and declines that can be nothing short of treacherous in miserable weather? If so, when it’s time to purchase a car you’re looking...
Symptoms of a Bad or Failing Coolant Temperature Switch (Sensor)
Common signs include poor fuel economy, black smoke coming from the engine, engine overheating, and the Check Engine Light turning on.
How Long Does a Heater Control Valve Last?
Keeping Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements of the coolant system can lead to a...