JordanR693

My 84 GS has lost alot of power. It is a pain to start and it over heats after driving.
I was thinking part of the loss of power could be timeing because last two times i turned off the car it backfired out of the exaust. the overheating problem i was eirther thinking it was the thermostat or the waterpump. I am new to this car because i just bought it like a week ago. I think that the water pump is in the engine right behind where the fan goes in but I wasn't sure. Im not very sure where the thermostat is and how to get to it but i think i have a pretty good idea. I was wondering if any one might be able to help me with this.

Thanks,
Jordan

Aviator 902S

Uh oh... Before you do anything else, pull all four spark plugs. Are the insulators on the business end dry and light tan or grey in color? If so, the overheating hasn't caused the coolant seals to leak--- yet. Once that happens it's rebuild time.

One of the symptoms of overheated rotaries is a gradual loss of power, owing to the expanding running clearances as the housings expand. Piston engines seize when overheated because their running clearances decrease as temps climb. The rotary won't seize, but it will lose compression and warp as it cools down after shut-down.

Evidence of ruptured coolant seals is a big-*** cloud of white smoke from the exhaust that does not go away even after operating temps have been reached, oil residue in the coolant, whitish sludge in the oil and spark plug insulators that have been polished to a high white shine due to ingestion of a steady diet of coolant leaking into the combustion chambers.

What causes these seals to rupture is overheating--- the excess heat causes the aluminum rotor housings to warp due to the different thermal coefficient of expension between the aluminum rotor housings and the cast iron intermediate and end plates. The coolant seals sandwiched between these warped housings are now allowed to leak, and it may take a few days or even months after the overheating incident for the symptoms to arise.

If the plugs look ok, the coolant has no oily residue, the oil has no white sludge in it and the coolant level stays up you may want to do a pressure test of the cooling system. Pressurize to at least 16psi and confirm that the pressure remains high without bleeding off. This will confirm that your seals are good.

Next, replace your thermostat. It is located under the attachment piece for the upper rad hose where the hose enters the engine. Just remove the two bolts holding this cap on and then pluck the old thermostat out and drop a new one in. Be sure to also replace the gasket with a new one.

BTW, the part of the engine where the upper rad hose clamps onto the engine is the water pump housing. The water pump is bolted to the front of this housing and has a pulley that is driven by the alternator drive belt. If you replace this water pump, be sure to replace not only the water pump gasket but also the gasket between the water pump housing and the engine. This gasket almost always breaks when attempting to separate the water pump from the water pump housing, and will leak if not replaced. Also, check your rad and intake manifold gasket for coolant leaks.

Finally, if you ever do see the temp guage creep up over 1/2 shut the engine off immediately. Do not try to drive the extra five minutes to the service station--- this is how these engines die. Walk, call a tow truck or wait for the engine to completely cool down before driving that extra five minutes into town, and even then only drive until the temp guage climbs to 1/2 before shutting it down again. These engines can last 0ver 200,000 miles if well-maintained and not boosted, but overheating is their achilles heel.