Engine got pretty hot

[Leros]

I know I need to get my car worked on. I'm just curious to know what the likely culprit is before I take it in. Also, what kind of garage should I take it to (a drive thru oil/general maintenance or a dealer or what)?

Today I drove my car 400 miles in 90F heat. This is the first time I have driven it a long distance in anything other than cold weather. The engine was running a bit warm ~50% between C and H on the temp gauge. 250 miles into my trip, the temp gauge got up to 80-90% between C and H. The A/C turned off of course. The A/C worked on and off as the car's temp fluctuated. I didn't leave it on, but I did test it as the temp gauge fluctuated.

I just got my oil changed yesterday so my fluids were checked and I have a hard time imagine the temps would fluctuate if my radiator was running dry. I assume the engine got hot so the car diverted all cooling to the engine which is why the A/C stopped working. So what would be the likely culprit? Bad temperature gauge, stuck pump, stuck valve, something else? I really have no idea how this stuff works.

Edit:

2000 Nissan Maxima GLE.
112,000 miles

 

[summit]

umm u were running your a/c, if your car is overheating, you need to turn on your heater to cool your engine down. i'm guessing it was a hard drive, up hills/mountains and your car just got oo much heat.

 

[boomerang]

The easiest thing to check (you can do it) is to take a look at the front of the radiator and make sure there isn't something blocking the airflow. You could have sucked up some debris on the road (plastic or paper bag for example) and it blocked airflow through the radiator. One thing to be aware of is that with the car now stopped and off, it's entirely possible whatever it was has fallen off and possibly even been carried away by the wind. You may not be able to see from above with the hood up, you may need to look from below.

Low coolant could very well be causing the symptoms you're describing. If you feel up to it, you can remove the radiator cap. The coolant level should be right up to the top. Please, please do this only when the car has sat overnight (engine cold) and with it not running.

I would take it to a general maintenance type of shop. It's not the type of work a quick oil change can do and the dealer is by far the most expensive place you could get the work done.

Year, make and model along with mileage is always helpful to know. The size of your engine can be very helpful too.

 

[Leros]

Originally posted by: Summit
umm u were running your a/c, if your car is overheating, you need to turn on your heater to cool your engine down. i'm guessing it was a hard drive, up hills/mountains and your car just got oo much heat.

I turned the A/C off once the engine started getting hot. I did turn the heater on.

It was a fairly easy drive. Flat ground, 70-80mph cruising most of the time. 90F degrees outside. The car shouldn't have acted the way it did.

 

[Leros]

Originally posted by: boomerang
The easiest thing to check (you can do it) is to take a look at the front of the radiator and make sure there isn't something blocking the airflow. You could have sucked up some debris on the road (plastic or paper bag for example) and it blocked airflow through the radiator. One thing to be aware of is that with the car now stopped and off, it's entirely possible whatever it was has fallen off and possibly even been carried away by the wind. You may not be able to see from above with the hood up, you may need to look from below.

Low coolant could very well be causing the symptoms you're describing. If you feel up to it, you can remove the radiator cap. The coolant level should be right up to the top. Please, please do this only when the car has sat overnight (engine cold) and with it not running.

I would take it to a general maintenance type of shop. It's not the type of work a quick oil change can do and the dealer is by far the most expensive place you could get the work done.

Year, make and model along with mileage is always helpful to know. The size of your engine can be very helpful too.

The coolant is fine. No blockage. I'll be taking it in today, so we'll see.

 

[M2008S]

read the freakin sticky on top of the garage forum

then READ MY POST.

the ac is powered by a serpentine or v belt, seperate from engine cooling. it has nothing to do with it. if its not working, its an AC issue which is seperate components. dont start thinking things. its rather simple.

if the car is overheating then there may be an issue. 50% between C and H isnt bad, theres probably something like NORMAL written between them on your gauge. your car isnt overheating unless its almost at the H. when theres a load on it (big hill, etc) its obviously going to get hotter.

let it cool down, see if theres fluid in the radiator and overflow bottle. if its low then its leaking and needs fixed. if its full and is overheating then its a thermostat or water pump issue, or the gauge could be bad. one other culprit is a head gasket issue, if the head gasket is bad youll have white smoke in your exhaust, hard to start, power loss, etc. another culprit is if you have an electric fan of some sort it may not be turning on to cool the antifreeze, or a regular fan may be going out.

so cliffs notes:

ac is seperate, completely. its powered simply by a belt and isnt hooked to your engine, its only bolted to it.

car gauge reads anything before 80% to H is ok. anything after is iffy

temp fluxuation is something that needs looked into at a shop

overheating could be caused by a bad thermostat, water pump, or head gasket. most of those items go bad because of normal wear and tear or excessive beating on your car. also a bad fan could cause a temp rise

 

[bruceb]

Depending on the age of the car and the maintenance that should be done on the
cooling system I would suggest doing the following:

Have the radiator and the engine flushed out.
Change the water pump if it is the original.
Change the Thermostat ... If it sticks Closed the engine will overheat. If it sticks open
you will take a long time to warm up the engine & heater in winter.
Test or replace the Radiator Pressure Cap.
When you fill the Antifreeze, you want a 50 / 50 Mix of antifreeze to water ... I personally
prefer distilled water ... that mix will give you the widest range of Freezing to Boilover protection.

Almost forgot: If it is a car with Electric Cooling Fans on the Radiator
check that they come on as they should. Usually around 200 Degrees
They are controlled by a sensor in the Radiator and a Relay for the current they need.

 

[Leros]

dp

 

[Leros]

I took it to a shop today and told them what happened. They looked at the entire cooling system. They checked the temperature sensor, the pump and some valve. The fluids were fine. They could not find anything wrong with the car. They let it run for about an hour, drove it around for 30 minutes and they could not get it to get hot. I wasn't surprised though. I only had the temperature issues and A/C issues 250 miles into the trip (400 miles total). After letting the car cool down for about 6 hours, I drove an additional 100 miles with no problems.

While the A/C may be a separate system, there is definitely a link between the engine temperature and the A/C functionality. When the temp gauge gets to a certain point, the A/C stopped putting out cold air. When I turned off the A/C the temp sensor started going down a bit (from 90% to 80%). When I pulled over and let things cool down (about 50%), the A/C would work again. Then if I started driving, once the temp gauge got to about 80%, the cold air stopped.

I'll be driving another 800 mile trip in a few weeks (400 each way). If I have problems then I'll take it into a dealership and have them take a much closer look at it. I'll take notes along the way if things start going bad again, so they have a better idea of what happened.

 

[Leros]

Originally posted by: bruceb
Have the radiator and the engine flushed out.
This does need to be done
Change the water pump if it is the original.
The garage I went to looked at the waterpump and said it was fine
Change the Thermostat ... If it sticks Closed the engine will overheat. If it sticks open
you will take a long time to warm up the engine & heater in winter.
Perhaps, butI had no problems with it warming up in the winter.
Test or replace the Radiator Pressure Cap.
I did that fairly recently, it was a bit loose.
When you fill the Antifreeze, you want a 50 / 50 Mix of antifreeze to water ... I personally
prefer distilled water ... that mix will give you the widest range of Freezing to Boilover protection.
Yup, this is what I have done

Almost forgot: If it is a car with Electric Cooling Fans on the Radiator
check that they come on as they should. Usually around 200 Degrees
They are controlled by a sensor in the Radiator and a Relay for the current they need.

 

[boomerang]

You still haven't given us any stats on the car. How many miles?

The car cools down when the A/C is turned off because the A/C condenser is ahead of the radiator. The heated air that passed through the condenser must them pass through the radiator. Turn off the A/C and the air passing through the radiator is cooler.

I've seen cars with a bucket load of leaves and debris packed between the condenser and radiator.

Is this an automatic or manual?

You've got a problem that is going to be difficult to diagnose because it only happens on long trips. How is any repair shop to fix such a problem? They're going to have to put in a recorder plugged into the car's computer to record exactly what is going on when the overheating occurs. And you're going to have to start the recording.

 

[Pacfanweb]

On many cars, the serpentine belt turns everything, so it's irrelevant to your problem.

Water pump: You're not out of the woods with this simply because a shop said it was working, and it's not easy to diagnose. What could be happening is the impeller on the pump is slipping...so it's turning enough to circulate some coolant, but not fast enough to circulate it like it needs. Really, the only way to check this is to remove the water pump, and if you do that you might as well replace it.

Thermostat: It's a possibility.....however you usually don't see them only acting up on long trips. When it comes down to it, it's a wise idea to replace it....it's cheap and usually easy to get at.

Radiator: Yep, gotta make sure it's not clogged up inside. Only way to do it is flush it. Also make sure a bunch of the fins aren't folded over and not allowing air to flow.

A/C: It stopped working because of the engine got hot. Either it was simply too hot to get heat transfer, or the computer simply cut it off to reduce the load on the engine and let the condenser cool down so it wouldn't be heating the air flowing across the radiator. Don't worry about the A/C, it's fine.

 

[Leros]

Originally posted by: boomerang
You still haven't given us any stats on the car. How many miles?

I had updated the OP yesterday. About 112k.

Originally posted by: Pacfanweb
Radiator: Yep, gotta make sure it's not clogged up inside. Only way to do it is flush it. Also make sure a bunch of the fins aren't folded over and not allowing air to flow.

The radiator looks fine externally. Getting a radiator flush is on my list of things to do.

Edit: The radiator has been flushed.