Coolant Warning Light Comes On, Temp Gauge Normal

[j.barleycorn]

Hi folks-

My coolant warning light has started to come on now and then. Seems to have no fixed pattern... sometimes it comes on when the engine is first started and cold, and goes off after 10 minutes @ 60 MPH. Sometimes it won't come on until 10 minutes after starting off.

It generally goes off and comes back on every 5 or 10 minutes. Lately once it comes on, it stays on more than it is off.

The temp gauge acts normally at all times, from cold to operating temperature, whether the light is on or not.

I checked past posts and didn't find any definitive answers. Thermostat? A sensor?

116,000 miles on the '92.

I appreciate any experienced help on this!

[falciott]

Hi folks-

My coolant warning light has started to come on now and then. Seems to have no fixed pattern... sometimes it comes on when the engine is first started and cold, and goes off after 10 minutes @ 60 MPH. Sometimes it won't come on until 10 minutes after starting off.

It generally goes off and comes back on every 5 or 10 minutes. Lately once it comes on, it stays on more than it is off.

The temp gauge acts normally at all times, from cold to operating temperature, whether the light is on or not.

I checked past posts and didn't find any definitive answers. Thermostat? A sensor?

116,000 miles on the '92.

I appreciate any experienced help on this!

Mine does the same, but it usually comes on at start then it goes away. It does that because it has a small crack in the coolant reservoir, and it looses coolant, so the level drops. Once i refill it, while it's cold of course, the light doesn't come on, till the level drops again.Have you checked your coolant level? Try adding some coolant while cold up to the top line, and see what happens.

[kevin317indy]

I have the exact same problem in my 92 ls400, but coolant level has been same for 6 months with no leak, has to be some kind of sensor. Just replaced water pump, timing belt, thermostat, and coolant flush. Light still comes on.

[mastertech]

there is a updated sensor and coolant jug to repair this..

[j.barleycorn]

Yep, I should have mentioned there has been no loss of coolant.

[sonyman]

The sensor in the tank may be faulty. Check the resistance against the factory repair manual.

[Lexls]

The sensor in the tank may be faulty. Check the resistance against the factory repair manual.

Agreed, check that. Also check the the water temp sensor and water sender gage sensor. Those are really easy to replace and cost less than $100 for both sensors.

[j.barleycorn]

Thanks, will do, and report back this weekend...

[acflye]

how did you situation turn out?

[yidaitianjiaous]

how did you situation turn out?

what the temp reading? My light is always on even i flushed the coolant and changed new. temp always reads in the middle of the gauge.. needle stays horizontal... is that normal temp ind?

[j.barleycorn]

Hi all-

I have decided to live with it and monitor it, as I agree it is just the sensor. Once the weather got cooler it would not come on as often... now that we are having a long Indian Summer, it is on more than off, but the temp gauge reads normal and all levels are where they belong. And since the brakes on 4Runner need doing (including those massive and expensive front calipers) I'm putting the $ where it will do the most good :)

And yes, the normal position for the temp gauge needle is in the middle of the gauge, just above the 2nd line from the bottom (and pointing to 1200 on the tach).