Not enough heat from heater

[Tony01013]

I’m kinda stumped on this one. I’m getting very tepid heat from my heater, even after driving it for over half anhour. Also, the temp reads to the very low side of normal. I’m thinking that I have a stuck open thermostat. I’ll check the coolant level and try to bleed any possible air out of it. I’m not trying to replace the thermostat if it isn’t the problem because it’s in a pain in the ass place to get to. Is there anyway I can tell if my thermostat is working or not? Thanks in advance.

Topic

[Matt]

Just start with bleeding the system. See Eric’s video:

http://www.youtube.com/watch?v=zUpXgAJ1gjU

I’d bet dollars to donuts (always wanted to use that phrase) this fixes yer problem. The spill free funnel is about $20 from most auto parts stores. If this doesn’t work, than a stuck open thermostat could cause the issue, but I would definitely start hear. If your thermostat is stuck open, it could cause poor fuel economy as well.

[skim3544]

You can take out the thermostat and throw it into a hot boiling water – as far as I know this is the only way to test the thermostat

[college man]

feel the upper and lower radiator hoses for a temp difference. do the same for the heater hoses.I don’t know what vehicle this is.if the engine temp
is low my money is on a stuck open thermostat.. keep us posted.

[Trcustoms719]

+1 on the stuck thermostat.
They are cheap enough, if it has not been replaced in awhile just do it as maintenance.
Feel both the hoses going into the heater core, if one is really hot (when up to full operating tem

[EricTheCarGuy]

Quoted From skim3544:

You can take out the thermostat and throw it into a hot boiling water – as far as I know this is the only way to test the thermostat

This is also the only way I know of testing them but to be honest as was also mentioned that they are cheep enough and if you have the old one out you might as well replace it and then bleed the system. The symptoms you describe are classic for a thermostat issue so I don’t think it would be too far off base to replace it and then recheck for the condition.

[Tony01013]

Thanks guys, I really appreciate all the replies. Especially Eric, I know you are wicked busy and it really shows dedication to your subscribers that you take the time to answer most of the questions and still run your site. By the way, It’s a ’98 Nissan Sentra w/ a 1.6L DOHC. I live in New England and it was a Tennessee car, so I’m thinking maybe the stat didn’t get a work out like it does up here. I checked the coolant and it’s pretty full. It has the orange coolant. What is the name of that coolant? I’m gonna get it up to temp with the cap off and see it that fixes the problem. Like I said before, the thermostat is in a difficult location, so that would be me last option. I’ll keep y’all posted.

[dreamer2355]

Do you have a scan tool that can read PID data? You could look at the coolant temperature when your in closed loop. It should be over 192.

As for coolant, stick with OEM. Do not mix brands or use universal C8-)

[EricTheCarGuy]

I would probably do the same thing, bleed the air out if there is any and if the symptom still exists I’d be looking into replacing that thermostat. Since it’s in such a tough spot I might recommend an OE unit just to be sure you don’t have problems with it in the future.

Good luck.

[college man]

hi Tony,

check your manual on the type of coolant your vehicle takes. I have owned nissans from the 90’s until current and never have they used the orange
dex cool coolant always the green.

[EricTheCarGuy]

You know that’s a good point, I might suspect that you have some ‘universal’ coolant in there because if memory serves Nissan has used just regular green coolant for years.

[Author]

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