89 Daytona, poor gas mileage/no heat or showing engine temp

[ChargedDust]

Not fond of the Bosch O2 sensors myself, I try to get the Standard brand when I need one, also used a Denso one once with no ill effects.

If I'm not mistaken, the threads for the plug on the T-stat housing are pipe thread, if you manage to get it out you can get a pipe thread bushing (reducer) and just put in a radiator petcock drain, that will allow you to bleed the system easily.

[daytona98]

Gonna stick with drilling a hole in the thermostat. Sounds to be the easiest way without jacking up the front a mile or using hot water. Least I have a machine shop at work to do it rather than hand drill. I don't wanna have to start dealing with fabricating custom tooling for what should be a simple job lol Why couldn't they just make a smart design in the first place.

As for o2's sorry should have mentionted it's a ES model with a 2.5 non-turbo four banger. Could really use a turbo haha. I was going to stick with either Denso or NGK, Bosch ones are quite a bit more for some reason.

Charged, Would you happen to have the Standard brand part number?

[ohnotagain]

if your temp isnt coming up that is the cause of your poor mileage. if the computer is seeing the engine as cold it dumps a LOT more fuel in the engine due to warm up enrichment.


if there is no heat then you definately have a mechanical problem.

swap out to a new T-stat first as its the cheapest, quickest, easiest thing to replace than can cause that problem. if you use one of the high quality t stats they already have the bleed hole in them. you can remove the pipe plug on the top side of the t stat housing to bleed air but it will most likely be very difficult to remove as it has threadlocker on it from the factory.

fill the radiator till its full, and start engine. coolant level in radiator should drop significantly after engine starts. top off radiator till its full and let engine continue to run. as temp comes up the coolant level will start to drop again as t stat begins to open. it most likely wont open up just idling durring cold weather, reach over and run the rpms up to around 3000 or so for about 10-15 seconds at a time until t stat opens up- you will see coolant level drop in radiator again when it does. top off coolant and reinstall radiator cap, you're done.
the coolant overflow bottle should be filled to the "hot" level mark once engine is up to operating temp. the coolant overflow bottle does 3 things- allows for overflow from an overheated engine to be captured, is an outlet for the cooling system to purge air, and when you shut off engine it will suck some coolant in from the overflow bottle as the cooling system depressurizes. at least thats the way they are supposed to work, lol.

if swapping t stats doesnt let engine come up to operating temp you most likely have a blown head gasket

[acannell]

dont buy any parts until you prove the existing part is bad, of which there are many ways for the parts youve mentioned.

you can treat the gauge issue as a completely seperate issue to your mpg issue. two things come to mind:

-wiring from sender to gauge intermittent somewhere. you can prove this with someone sitting in the car watching the gauge while you either wiggle the wiring, or connect the harness in a way where it forces the signal to a false maximum (full high or full low). do this with the engine warmed up and the gauge should bounce around while you wiggle it if the harness is bad.

-gauge cluster solder connections cracked. this is not so bad to fix, but you have to pull the cluster to check it. this may be an issue ALONG with the harness being bad

you can check the sender with an ohmmeter, but I dont remember the proper resistance to temperature relationship, although its on the dodge garage and possibly the fsm and even haynes.

you can unplug the sender and do something to the harness pins to force the gauge to read either very high or low, i dont remember how, but you can figure it out using the wiring diagram.

check, reset, and check your ecu codes with the check engine light.

as a crude test, you could let the engine "warm up" for 10 minutes, then unplug the tstat housing coolant sensor..the fan should come on, indicating the ECU sees a change in temperature


buy a OBD 2000 tool if you plan on keeping this car, $75 and its priceless, will tell you real time sensor data the ECU sees

[NAJ]

Very easy to check engine temp(19 posts and not fixed... really???)

Backprobe the CTS connector and check voltage with the engine running.
As engine warms voltage changes, at temp cooling fan will cycle on.
Also...Is there a Code 17 stored in memory???
Simple Chrysler Code...
"Engine Coolant Temp Remains Below Normal Operating Temp"
FIX..."Replace Thermostat"

BACKPROBING THE CTS



COOLANT TEMP SENSOR VOLTAGE CHART



DRAINING AND REFILLING 2.2L/2.5L COOLING SYSTEM

[acannell]

wow Naj you really are the human service manual lol!

[daytona98]

Wow NAJ I appreciate the pics. Plan on doing it this weekend so I'll let you know how the results went. I ordered a temp switch, o2, coolant temp sensor and new thermostat just to be on the safe side. Don't mind having spares around :)