Smoke coming from back of engine

DUWHOP31

MEMBER
2007 NISSAN MAXIMA
3.5L
6 CYL
2WD
AUTOMATIC
235,000 MILES

The other day I took my Mom to Walmart and dropped her off up front and then parked, but I left the car running until she got back (about 25-30 minutes) around that time I smelled something coming from the engine (but can't make out what it is) as well as a little bit of smoke coming up from the back of the engine (if you popped the hood and where in front of the car looking at it) as well as I could hear the coolant in the radiator like bubbling up, but not leaking out anywhere under the car, from the cooling system or out from the cap of the radiator. I just don't know what this could be or if I need to worry about it?

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3 Replies

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

It sounds as though the engine was overheating. Was the indicator lamp on in the vehicle or the gauge showing it was hot? Also, if you saw the smoke/steam near the rear/firewall, check the heater hoses. They may have been leaking.

Take a look at pic 1 below. I highlighted the heater hoses that come from the engine. They will go to the firewall where they attach to the heater core. Check there for leaks.

Also, if nothing is found, you may want to pressure test the system. That way, you can carefully check for leaks without getting burned. Here is a link showing how that is done:

https://www.2carpros.com/articles/radiator-pressure-test

You will need the pressure tester, but most parts stores will lend one to you.

Let me know if this helps and what you find. Also, let me know if I can help in any way.

Take care,

Joe

See pic below.

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Thursday, March 31st, 2022 AT 8:13 PM

DUWHOP31

MEMBER
151 POSTS

No, it's not running hot at all the gauge is normal and I have an OBDII scanner plugged in, and the temperature stays normal. When I check the radiator and reservoir they are both completely full. It just barely was smoking the main thing is there's a smell that almost smells like something burning, I'm not 100% sure, but it smells a little different. Which hoses should I check?

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Sunday, April 3rd, 2022 AT 9:04 AM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

You can't see them in the pics. If you look below, I included the piping for the cooling system. Letter A is located where the upper radiator hose connects to the engine. So, follow the upper hose to the engine to locate that point. Letters B and D are the inlet and outlet for the heater. Check those areas.

You indicated an odd smell. Was is it like a sweet smell? That is what antifreeze is commonly referred to as smelling.

Let me know.

Joe

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