This has all been a big headache, figured i'd post up and see if you guys/gals had any ideas.

So, i'm driving down the road and my temperature gauge slowly builds up to 3/4, then, after a minute or two, it drops back down to 1/2 where it usually sits.

I change the thermostat, rad cap, coolant temperature sensor and do the fan wire mod, to no avail. The temp gauge still buids up to 3/4 and slowly goes back down to 1/2. I cannot, for the life of me, figure out what is causing this.

Oh, and the coolant doesn't boil into the overflow, no white smoke, no cooant in the oil or vice-versa.

Any idea what could be causing my problem?

Thanks in advance.

95 Talon ESi
Cold Air Intake
Removed Rear Seats, Rear Seatbelts, Spare Tire/Cover, Jack, Washer Fluid Reservoir, Spoiler, Rear Wiper.

Air in the system perhaps?
Try "burping" the system.
Remove the cap, let the car run for a while to expel any air that might be inside.

1998 Eclipse RS-T - Totaled 4/23/09 -
1998 Eclipse GST - Stroked 2.3l, HX40 fed: Build in progress
2010 Subaru Outback Limited

I hate hipsters.

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

Water pump was recenty changed, and it does it consistently.

95 Talon ESi
Cold Air Intake
Removed Rear Seats, Rear Seatbelts, Spare Tire/Cover, Jack, Washer Fluid Reservoir, Spoiler, Rear Wiper.

Welcome to my world. I found that I have 2 very slow water leaks and that keeps the system from pressurizing. Check the hose that runs over the exhaust manifold and see if it is slowly dripping. That is my current leak and since it doesn't leak a whole lot, it was hard to track down.

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agree with the above reply. Borrow one of those coolant system pressure testers. Test the cap while your at it. Brands and stores where you bought said items?Including the pump? For the time that I worked at an autoparts store, you would be surprised at the number of items that were dead to begin with.

Check all the hoses, Pin hole leaks and cracks are annoying.

another thing, which sensor did you replace? both? hows the ecu?

Member # 751


FOUNDER of the Central Cali chapter of 2GNT!
(I got kicked out after I refused to go Cow tiping) - Hehehe you know who this is for

bought the thermostat at Advance Auto, along with the CTS and the sending unit.

changed the coolant in it yesterday and now i can't drive it at al because the temp gauge is going al the way up and staying, tried burping the system today, still overheats.

i'm lost.

95 Talon ESi
Cold Air Intake
Removed Rear Seats, Rear Seatbelts, Spare Tire/Cover, Jack, Washer Fluid Reservoir, Spoiler, Rear Wiper.

Does the temp drop if you turn the heater on? (full blast)

You say you changed your coolant out; Did you use enough to completely fill the system? (Stupid question I know, but you'd be surprised around here.)

If you have someone else around have them give it some gas while parked, so you can check if you're spraying coolant out of a small hole or something.

1998 Eclipse RS-T - Totaled 4/23/09 -
1998 Eclipse GST - Stroked 2.3l, HX40 fed: Build in progress
2010 Subaru Outback Limited

I hate hipsters.

You have a blown headgasket. Congrats!

______________________________
If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.

'95 Eclipse TurboGS (garage deco)
'95 TSi AWD (restoring a survivor)
'97 Talon ESi-T (poor impulse control)
'99 Eclipse RS-T (daily beater)
'13 Evo X (mostly stock)
'17 Sienna (Middle Aged Dad Mobile)



Factory Service Manuals: http://nawdu.de/files/

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

yup sounds like a Hg. you verified that the pump is good right?

My blown hg wouldnt show any of the usual signs. I guess it would only leak under the pressures of the combustion process.

Are you positive that both sensors are good? whats the temp read out through the OBD port?

When I was having problems with the bad sensor and fans not coming on, all the tests showed the sensor was good. But soon as I swapped it( second time), everything was fine.

Member # 751


FOUNDER of the Central Cali chapter of 2GNT!
(I got kicked out after I refused to go Cow tiping) - Hehehe you know who this is for

problem solved, ended up being air in the system.

95 Talon ESi
Cold Air Intake
Removed Rear Seats, Rear Seatbelts, Spare Tire/Cover, Jack, Washer Fluid Reservoir, Spoiler, Rear Wiper.

I guess I'm a hair late, but I've heard this many times, but usually after changing a heater core. Someone had said that there was some strange clause like you come to a stop quick and the temp would raise up... heard of that a bunch on the 3g's.

/>

'95 GS w/ t3/t4b
FMIC, diy piping & RFL BOV
MS2-Extra Fuel&Spark
50 lb/hr Holley injectors w/ 1:1 RRFPR
JE 8.8:1 dish w/ Hastings Rings
Eagle Rods w/ ARP bolts
ARP Head studs
Mild port/polish head
3" custom DP/cat section, 3" PIT catback
dual MBC - 12 psi / 20psi

take off the coolant cap, top off the fluid in there. start the engine and turn on your heater full blast hot. go back to the front of the car and keep topping off the fluid until absoloutely no more air bubbles come out for a few minutes. shut off the engine and immediately reinstall the coolant cap. make sure your reservoir has plenty of fluid and that there aren't any cracks in the cap or lines for air to get sucked back into the system.

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

I did all that and still a no go... I disabled my heating system. So the part that has the hoses that connect to the heater core in the firewall has been bypassed. I did the whole fill and run and add coolant for more than a few minutes. My thing is will the bubble eventually escape the system? Or do I have to keep trial and error with the bleeding of coolant system? This is ticking me off! And all i really wanted to do was change out my brakes... Then I said hell, let me replace hoses, coolant and other things cuz it hasnt been done in a long while and texas heat is scorchin! So I do that and now it gets hotter than texas!! GRRRR.

EDIT:
Board was having issues. Added reply to this post, then saw double post below. Admin powers FTW, IB TL, ETC.

Ok... So I got a reverse radiator flush done, which essentially rids the radiator and block of any possible airbubbles in the system. Had the headgasket checked and it shows ok. Car still gets hot. Old coolant that came out was clean. No smoke, No mixture of coolant and or oil... What the hell!! What else could it be? New sensors, new hoses, fan does come on. Radiator is fairly new, less than a year. Gauge goes over 3/4 high. I do notice that if I'm coasting down a hill with the car in gear then the temp starts to drop. That's weird to me. Water pump is fairly new too, but that is not to say I'm ruling that out. Any more ideas people? Thanx.

Is your radiator NEW or junkyard new to your car? And not to sound like an ass but did you put the thermostat in correctly? Just had people say that it runs hot after a new therm. put in and turns out it's upside-down/backwards... Also are your fans commin on properly? I'd think goin down the road there'd be enough airflow they shouldn't be needed (45mph+). The coast/cooling effect is usually a fan clutch or head gasket, and we don't use fan clutches... Maybe you have one of those wonderful pooly-designed and recalled factory head gaskets that doesn't line up with the cooling passages?

/>

'95 GS w/ t3/t4b
FMIC, diy piping & RFL BOV
MS2-Extra Fuel&Spark
50 lb/hr Holley injectors w/ 1:1 RRFPR
JE 8.8:1 dish w/ Hastings Rings
Eagle Rods w/ ARP bolts
ARP Head studs
Mild port/polish head
3" custom DP/cat section, 3" PIT catback
dual MBC - 12 psi / 20psi

yes sir, the radiator is new, not new used. The headgasket was put fine and like i said it never gave me this issue before. and the fans do kick on. Here's what I found interesting. I downpipe is cracked in the back and is aiming almost directly at the thermostat housing and sensor. In fact if you put ur hand in front of the housing and rev the car you can feel the exhaust blowing on it. With one of them laser pointer thermometers, The side of the sensor facing the downpipe reads at 225 degrees, the opposite side that is away from the down pipe reads 147 degrees and so on... So do you think it's possible that the exhaust heat is heating up the sensor and housing enough to give false reading? I have no coolant bubbling, no smoke, no mixure or anything. So even though the car isn't apparently overheating, but the gauge reads high, scares the beegeebies out of me! lol... Will have to get the down pipe fixed to see if this fixes the problem. Will keep you all updated.

wow, that's a new one to me but I can't say that I'm terribly surprised.

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

Maybe I just missed something all these years but I have never seen my temp guage at 3/4. I thought the Eclipse temp guage stayed at 1/2 unless you overheated and then it shot to max. I was under the impression that Mitsu did this to prevent service calls.

hahaha. I've seen mine shoot up, blew a heater hose and it spiked just before my low coolant light came on. It was mostly a steam reading, but scary nontheless. And yeah, that is a new one, and very possible.

/>

'95 GS w/ t3/t4b
FMIC, diy piping & RFL BOV
MS2-Extra Fuel&Spark
50 lb/hr Holley injectors w/ 1:1 RRFPR
JE 8.8:1 dish w/ Hastings Rings
Eagle Rods w/ ARP bolts
ARP Head studs
Mild port/polish head
3" custom DP/cat section, 3" PIT catback
dual MBC - 12 psi / 20psi