So a few days ago my check engine light went on. Guys at the auto parts store couldn’t get their OBD reader to talk to it, but said probably fluids and I should have them checked out. So today on the way home during a cold snap, my engine temp light goes on. So I’m panicking, trying to get off the highway before my engine blows up, but by the time I get to the off ramp, it’s back down to normal. It’s fine the rest of the way home, but naturally I’m jumpy.
Talked to a friend of mine online who said check the coolant. Lo and behold, I’ve got hardly any at all. So looks like they were right about the fluids. So I’m off to the auto parts store first thing tomorrow to get it topped up, but I just wanted to check here and see if there’s another possibility, and also see if anyone knows why it went up and then back down again–only differences were I was crawling when it went up, and then actually got to move a little and also turned on the window defroster. Dunno if either of those things would make the temp drop. Could it maybe be the thermostat?
Anyway, appreciate any good thoughts.
PS: Since their OBD scanner wasn’t working, I’ve got one on order for myself. Won’t be here til Thursday though, so obviously like to get this fixed before then!
Sounds like you have a coolant leak to me… Have you seen coolant in the driveway or where you park your car? If you do have a leak you need to of course fix it…and refill the cooling system PROPERLY… You do not want an air bubble in your system… Many vehicles provide a nice bleed nipple near the thermostat to do just that…others have a special fill procedure usually telling you to top it off and then fill up the overflow reservoir and go thru several heat and cool cycles to get the coolant up to the correct level with no air pockets.
The reason the temp needle jumps up and down is because when you are low on coolant and the engine is cold…the coolant is not expanded…when you get hot the coolant volume increases to due temp and this may make it contact the temp sensor…so at one temp it cant reach the temp sensor…and when hot it sort of splashes the temp sensor…this will make it jump all over the place. Turning your heater on in this instance is the best thing you could do as the heater core is acting like a little radiator (which it is) this will drop your temp a bit…this is what you do in the summer when you are overheating…Turn on the blower motor with the heat on…its not xactly comfortable…but your engine will thank you
If this were my vehicle I would fill the rad with water while it is still near empty and then look for leaks…find them and fix them… and before you fill up with coolant you could change the thermostat while you are at it…couldn’t hurt…I bet you are still on the original anywho…no?
OK, that makes sense. I haven’t seen any leaks per se. But in fairness I haven’t looked. I’ll check in the morning.
As to the bubble thing, manual doesn’t say anything about doing any of that, it mostly goes on about using the right coolant and distilled water and no rust inhibitors, seal the cap and so on.
Funnily enough, it says don’t change out the thermostat, only if it’s absolutely necessary.
Anyway, I’ll go ahead and try checking for leaks tomorrow and if not, I’ll just fill 'er up and see if that gets me good, keep an eye out for leaks and fluid level drops of the next couple weeks, I think. Definitely appreciate the explanation of what was going on under the hood. Sounds like I’m on the right track at least.
Anyway, thanks much!
No problem…If you are going about it that way then fill her up with the proper mix of coolant and water…you can buy it already mixed and ready to pour into the system… If you were ready to look for leaks and actually work on the car I was suggesting to use just water for the leak test so as not to waste coolant… You are on the right track for sure…
Honda Blackbird nailed it on the head. I won’t go through the trouble of saying the same thing since they worded it so well.
Pay attention too if it seems your windows are steaming, not fogging, steaming and you have a sweet almost pancake syrup smell when you turn on your heater. That would indicate heater core. my '96 taurus did that and I replaced everything in the heating system except for the radiator. that cost some dough! a heater core job is NO walk in the park.
might have to check coolant level about once a week, depending on how much it leaks out. Like Blackbird said, try to look for leaks. Make sure your motor oil isn’t turning gray.
That OBD2 Code Reader Should Be Handy To Have, But Probably Not For This Application.
You already know that coolant is being leaked or consumed and that the engine gave a high temperature indication. You need to find either an external leak (to the ground or in the engine compartment which sometimes burns or steams away) or an internal leak (into the radiator, transmission, or engine). A leak into the engine’s combustion chambers can be turned to steam and exit the tailpipe. On a cold day see if your car is billowing more exhaust than the norm.
Find where the coolant is going and that will lead you to a faulty radiator, thermostat, cooling fan, head gasket, intake manifold gasket, water pump, hose, radiator cap, reservoir, etcetera.
Well, put some antifreeze in first thing, and by the time I put the bottle away it was draining. Verified puddle on the ground, then off to the garage. Turns out it was the thermostat assembly. Took all morning but they got it good. Even got my heat back (lately it would only heat if I were driving over, say, 40). Thanks to everyone who helped me diagnose the situation!
It’s Important To Keep Checking The Coolant Frequently After A Problem Like This One Until You’re Certain That The Leak(s) / Consumption Problem(s) Are Resolved.
Is this a 2.7L engine ? Many a “mechanic” has been fooled by a water pump weep hole on these engines, located almost at the thermostat housing. The pump is “inside” the engine and the weep hole channels any leaks to the ouside. It’s very unlikely for a “thermostat assembly”/gasket to begin leaking, but it could happen.
Justkelly, just keep checking for a while to be safe. That’s my advice. No heat is uncomfortable, but overheating can do engine damage.
Good luck. I hope they "got it good."