The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support RTM Racing
Please Support Morrison Fabrication

2G Help me with a diagnosis?

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Flippacase1

Probationary Member
12
0
Nov 3, 2014
Attleboro, Massachusetts
Hey everyone, so I have been having some issues with my 98 eclipse rs (420a, n/t, 5 speed) since I bought it a couple months ago. To describe the issues:
-Runs rough at low rpms. Won't idle unless I give it some gas, smooths out completely above like 1500rpms.
My initial thoughts on this issue were some kind of vaccum leak but that wasnt the case. After some reading on here I replaced the pcv valve, cleaned the egr valve, cleaned the throttle body, and cleaned the iac. All had no noticeable affect.

Then today when I was driving my oil light came on for a few seconds during a sharp turn and then went off again. That wasn't a big deal but later in the day I was on a short drive, under ten miles, and I noticed my temperature gauge was creeping up past the 3/4 point. I cranked up the heat to draw it away from the engine and thankfully I reached my destination before the temp got into the red. When I turned off the car steam was pouring out of the hood and when I popped the hood I saw that the coolant was boiling out of the reservoir. I topped off the coolant a few weeks ago and judging by my cars soaked engine bay and bumper and driveway, the overheating wasn't caused by lack of coolant. After a few hours I went for a drive and there were no problems with overheating whatsoever.

What do we think? I've read a bunch of possibilities and I think I might know what it is, but before I shell out a bunch of money on something that might not even be causing the problem I figured I'd get a second opinion or two...or ten. So if you guys could help me out that'd be awesome!
 
Check to make sure fans are working properly. If they are id recommend relpacing thermostat and either getting the radiator cleaned or replaced. Check the oil cap and dip stick to make sure no damage was done to head gasket. If it has sludge like chocolate your gasket is done. If its not just start with the things I said in that order.
Check fans to make sure theyre activating
Replace thermostat
Clean radiator or replace.
 
Check your radiator cap, it could cause an intermittent issue and leak coolant out. By the valve not pulling a vacuum and all the coolant will leak out the overflow reservoir.
 
Hey guys thanks for the responses! My fear is that it is a head gasket issue. In addition to the symptoms I listed above I was also throwing a CEL for random misfires. Do you think a head gasket could be responsible for rough idle, overheating, collant boiling and flowing out of the reserve, and random misfire codes? Or is it possible that changing a radiator cap and thermostat could fix all my issues LOL?
 
What Dsm dreamer said. Could be head gasket but I would start eliminating the (cheapest things) first and work your way to the bigger problem. At least you'll have peace of mind on the parts you do replace.
 
Okay guys, so I have an update. I was driving today (the overheating has only been an intermittent issue so I've continued to press my luck) And wouldn't you know it, car starts overheating. Its gotten to the point that I can somewhat predict when it'll happen because my car's heater stays blowing out cold air. So I was driving today and the temp gauge started creeping up so I pulled over to let it cool down. After about 15 minutes it got back down to normal operating temp and I set off to get home before it overheated again. As I was driving I had the same symptoms as before, the temp was rising steadily towards overheating and my heat was blowing out frigid air (it was like 15 degrees in massachusetts today) and just as the temp gauge was getting dangerously high and I was about to admit defeat and pull over again...BAM!!! I felt a burst of warm air from the heater vents and my temperature gauge almost instantly fell back down to normal operating temps. Soooooooo my thought is that maybe the thermostat is intermittently getting stuck open/closed?! Maybe thats why my car seemed to all of a sudden be completely fine? What are your thoughts oh wise ones?
 
If this was me, I wouldn't even drive the car until I replaced the Thermostat and Cap. Just cause if you keep driving it like that, I'm sure if you don't need a head gasket now you soon will. Not only that with the temps being so cold up here that head is gong to warp do to the heat of the engine and the below freezing temps in the northeast. Plus this may lead to having to buy a new head and or rebuilding your head / having it resurfaced and that's where it can cost some $$$$. So if you are not trying to Spend a ton of money now, I would listen to what every reply has today you since day one and spend the $30 or so $ now than to have to fork out $500-$1000 plus dollars for a new head gasket as well as having the head fully disassembled and re-surfaced etc.... But that is just my $0.02
 
Alrighty guys, I appreciate the help and apologize for being a big dumb idiot and continuing to drive it. I went to the parts store today (in my brother's jeep) and grabbed a radiator cap, a new thermostat w/ gasket, and some new coolant for a flush while I was at it. When I took of the radiator cap and the main hose you'll never guess what I found...SOLID ICE. apparently my coolant was a little too much water and not enough antifreeze. I unplugged the drain at the bottom of the radiator and nothing. Not even a drop. My radiator was completely frozen. I grabbed a gallon jug filed with warm water to see if it would go down into the radiator to thaw things out a bit but it wouldn't even go down the filler neck. I grabbed my heat gun and crawled under the car and started at the radiator. After about 5 minutes I started getting some rusty drips, and after about 10 minutes with the heat gun there was an eruption of shit colored water. I grabbed my gallon of water and poured it down the filler neck and thank god it came right out the bottom. I continued to do so until the water coming out was completely clear. Then I popped in the new thermostat, poured in the new 50/50 mix of coolant, and topped it off by screwing on my brand spanking new radiator cap. We shall see if the issue is resolved, but thanks for the opinions everyone!
 
Soooooo...sorry to be a pain in the ass but I've got another issue that I could use opinions on. So when my car overheated the other day, and I should've mentioned this before, my battery also died. When I tried to start the car after the temp came down it tried to turn over then my dashlights all dimmed and nothing. I got a jump from a buddy of mine and got home only to replace the thermostat, radiator cap, and flush out the frozen radiator the next day. After changing all those goodies I went to start the car again and the same exact thing happened. I jumped the car and ran it for about 20 minutes to top off the coolant and make sure it could get everywhere so I wouldn't have any issues with freezing again, but I didn't drive anywhere. Today, I decided to take a maiden journey with the new goodies and THE SAME THING HAPPENED AGAIN. It tried to turn over only to slow down and all the lights dimmed and then nothing.:banghead:
Is this problem likely somehow related to the overheating issue?!? Because I have never had a problem with the battery before. Is it because its like 1 degree outside and the battery is just tired? Is it because I didn't drive around after the jump so the alternator didn't charge the battery? All of my belts seem fine so I don't think its that. Tell me what you think because this is getting prettyyy annoying LOL.
 
Your battery may be shot. Jumping it and driving around helps but you really need to use a charger to charge it if it's drained. These cars rely heavily on proper voltage supply. I would take the battery out and go have it tested first. Then if it's good, put it on charge and then put in the car and go get the alternator tested to make sure it isn't bad. Even if it turns out your battery is done with, still take the car and have the alternator tested after you get the new battery. Personally, I'd jump start the car, let it warm up and see how the overheating issue is and if it checks out, drive to your local auto parts store or mechanic and have the charging system checked and the battery. Autozone where I'm at does it for free, not sure where you'd be going so it's up to you. Most importantly with as cold as it is DO NOT let the car overheat anymore or serious damage will happen. Hope this helps.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top