2000 Oldsmobile Bravada. Engine is running hot, and I have intermittent heat. I've replaced the thermostate last week and now the problem is worse than before. Engine will get up to 260 check gauges light comes on then it's as if the thermostate opens and the engine temp drops to normal. Before the thermostat was replaced the heat would work then the engine temp would drop. Help me please

do you have coolant flow through heater core? Does the blower motor work? If that checks out, maybe a temp door under the dash has a problem?

Check the heater core to see if it is hot on both tubes entering the firewall. If it is, then the inside should blow hot air as well. If not hot, then the heater core is plugged and will have to be flushed out or replaced.

If the heater core is hot but the inside is cool, then the blend door actuator may be bad.

I WOULD SAY YES BECAUSE THE LUCAS FUEL INJECTOR CLEANER IS JUST HELPING THE INJECTOR SPRAY BETTER

Sounds like you have a connection issue.

hi you might need your AC recharging, after a time the gas from the AC tends to leak out ( as all gasses do ) you could try getting this boosted, better not say that if american might get wrong idea, maybe recharged is a better way of saying it..lol, hope this helps

Did you run engine from cold, with heater on when you refilled the system? Try again, rad cap off, with heater on, and let engine get up to operating temperature, make sure you have good flow through rad ,leave cap off, until rad fan comes on to cool returning coolant to rad at least twice. Give engine a little extra rev, for 5 seconds or so, every once in a while to make sure flow getting through heater core, and add coolant as necessary. See if that helps, as it may just be an airlock in system. If your cooling system has any bleed screws incorporated, crack them once in a while as well.

Yes, your thermostat is bad, and it's incredibly easy to fix. Go to PepBoys (or whatever), get the part, open the cap when the engine is cold, and switch the part. My mother can do it.

Hello the bravada and the s10 blazer are bad about the heater cores air locking or either stopping up. Disconnect the heater hoses at the firewall and run a water hose to the inlet then try the outlet until the water is clear of debris then reconnect and refill with coolant remember 50/50 coolant water. Pure coolant will freeze and so will pure water. Thank you

check the thermostat and coolant level

You may have an air bubble in your coolant system. If so, use a large coolant funnel designed to purge out air bubbles. The funnel attaches to your radiator with cap removed. Check it out on line. It costs about $25.