desertcox05
New Member
my local rad shop said they could core a stock rad. but i don't remember how much it would cost.
Cooling problems
- Thread starter Rubedogg
- Start date
This weekend I burped the system and replaced the radiator cap. With the A/C off, it doesn't heat up too bad. The temp gage might get to the "M". But when I turned the A/C on in the afternoon on Saturday with outside air temp about 85 degrees, it started getting hot again. This morning, the air temp was only about 65 and the engine temp didn't get above the "N". It also seems to take awhile for the car to heat up, especially when it's cool out. Yesterday I had driven about 5 or 6 miles before the temp needle got above the white line. To me, this indicates a possible sticking thermostat. This is the same symptom I had with the old thermostat though. Is it possible I put in a bum thermostat? Do Mr. Gasket t-stats have this problem? I realize the gage is crap but it is acting funny relative to how it acted in the past.
When I burped the system, I didn't notice any air bubbling out so I can only assume all the air is out of the system.
I also checked the grounds. It looks like I have 3 small grounds on the front panel so I cleaned those up. I thought it was weird that they're attached to painted metal though. Shouldn't the metal be bare to get the best conductivity? I figured what the heck though, it came from the factory like this so it's probably fine. What did bother me though is that the battery to engine ground was either cut or tore off so I need to rig up my own fix for that. I also couldn't find an engine to body ground. Could anyone give me some pointers on rigging up my own grounds? I think that might solve some of my electrical problems and could even fix this cooling issue as noted above by Bullitt95.
I'm thinking the next step after I repair the grounds, if it's still running hot, is to tear out the thermostat and just let the coolant flow unrestricted. That way, if it's still getting hot, it's either the radiator or water pump. What do you all think?
Thanks for the tips so far fellas!
When I burped the system, I didn't notice any air bubbling out so I can only assume all the air is out of the system.
I also checked the grounds. It looks like I have 3 small grounds on the front panel so I cleaned those up. I thought it was weird that they're attached to painted metal though. Shouldn't the metal be bare to get the best conductivity? I figured what the heck though, it came from the factory like this so it's probably fine. What did bother me though is that the battery to engine ground was either cut or tore off so I need to rig up my own fix for that. I also couldn't find an engine to body ground. Could anyone give me some pointers on rigging up my own grounds? I think that might solve some of my electrical problems and could even fix this cooling issue as noted above by Bullitt95.
I'm thinking the next step after I repair the grounds, if it's still running hot, is to tear out the thermostat and just let the coolant flow unrestricted. That way, if it's still getting hot, it's either the radiator or water pump. What do you all think?
Thanks for the tips so far fellas!
Buy a Mr Gasket thermostat, boil it in water and make sure it works. Then install it. If the car still gets hot then replace the radiator, if it still gets hot replace the water pump, etc etc...work your way back.
Does it run cooler at speed or while idling (stationary)?
Some folks have reported issues with Mr G stats of late.
I noted the same thing with the sheetmetal grounds on the front clip. I had taken mine down to bare metal (mine's certainly not a show car).
There's a motor to chassis ground on the driver's side. It's a metal strap. I used a 4 AWG cable to mirror this ground on the passenger side (motor side of motor mount to the frame, near the ABS pump).
Some folks have reported issues with Mr G stats of late.
I noted the same thing with the sheetmetal grounds on the front clip. I had taken mine down to bare metal (mine's certainly not a show car).
There's a motor to chassis ground on the driver's side. It's a metal strap. I used a 4 AWG cable to mirror this ground on the passenger side (motor side of motor mount to the frame, near the ABS pump).
Dino Dino Bambino
15 Year Member
I had a similar problem in the past where the dash gauge needle would be on A while driving on the highway, and later discovered that the actual temp. was only 194*F when I checked it with my infrared thermometer. I'd also noticed that all the gauges would flicker if I added an electrical load (e.g. headlights on or AC on). I added a ground cable from the upper intake to the firewall and that cured it. The gauge reading fell from A down to O at a coolant temp. of 194*F and the other gauges no longer flickered when an electrical load was added. Now I can trust my stock temp. gauge knowing that the difference from one letter to the next is 7*F (A is actually 215*F).
Yes, even some brand new t'stats have been known to be bad so test it in a pan of boiling water to make sure it opens. I once bought a new OEM t'stat and it didn't open at all so I promptly returned it to the parts shop. Got a Mr. Gasket 180* t'stat instead and 18 months on, it's still good.
Man, I bet that felt good to get fixed! I'm definitely thinking this is mainly an electrical problem. I hesitate to rip apart my cooling system when (this is my theory anyway) it could just be the car heating up to normal operating temp, plus a warm day outside increasing underhood temps, which then cause the grounds to get worse due to the heat. I have some free time tomorrow so I'll be heading to the parts store to pick up a couple (4 AWG?) cables to act as ground straps. I'm crossing my fingers!
If the grounds are fixed but it's still overheating as indicated by my gage, checking the thermostat in boiling water will be my next step.
The temperature is indicating it is running hotter at higher speeds. What has been happening is the car heats up slowly after start-up and gradually heats up to the "A" or "L" on the temp gage if I am cruising on the highway. This usually happens slowly, like over the course of hours. If I am doing the stop-and-go dance in traffic, it doesn't usually heat up past the "R" or "M". However, if I turn on the A/C, all bets are off and it will get HOT due to the extra load, I guess. Also, if I keep the A/C on, underhood temps will get high enough to cause that low pressure switch to malfunction and the A/C will just stop working. I think that's what is going on anyway.
If the temperature gage is at all functioning correctly and the car really is getting hotter at highway speeds, that would be indicative of a bad water pump, correct? The theory being the impeller would most likely be worn and/or corroded bad enough to not pump very efficiently at the higher RPM's. Some have alluded to this in earlier posts. I'm thinking it would most likely not be the radiator since the radiator should be more efficient at higher speeds, not less, since you have more airflow. Is my reasoning correct?
99FiveOh
15 Year Member
No. If the radiator is corroded inside, your theory about the water pump at higher speeds would also apply to the radiator. The radiator can flow enough coolant to cool the car at low speeds, but it creates a huge restriction at higher speeds causing the motor to starve for cooler water.
I think you need to replace your radiator with a stock replacement and you'll be fine. I've been here before and a new radiator worked wonders for my car.
I think you need to replace your radiator with a stock replacement and you'll be fine. I've been here before and a new radiator worked wonders for my car.
I agree about the radiator sentiments - it sounds like you simply cannot reject enough heat. Otherwise, ambient air flow at highway speeds shoud promote more cooling than the fan does.
IMHO if you see some triple digit temps, get something bigger than a stock radiator however.
IMHO if you see some triple digit temps, get something bigger than a stock radiator however.
five0xpres
New Member
I've been having the same issue with my temp gauge jumping around from one side to the other and then settling around the "L" in NORMAL. I replaced the t'stat and it moved the needle down to the middle of the M and the A, but it would still surge. Today I replaced the temp switch (sending unit) and it read a little bit lower, but still higher than what it did prior to this odd behavior.
After searching these forums and finding this post with several suggestions, I started to check my grounds because I also noticed that my oil pressure gauge was running high and the needles would "wiggle" if I put a draw on the electrical system (ie: lighting up the brake lights or holding the power window switch down for an extra second once the window hit the travel stop). The grounds at the battery looked good and the engine to frame ground was solid as well.
In an attempt to solve this issue, I wired my own ground wire from the point where the hood ground strap is attached to the passenger-side fender to the rear bolt on the upper intake manifold. I test drove the car into town on some errands and once the engine was warmed up, the needle was between the O and the R with outside temps in the 93F+ range. I'll be able to report later what it reads in the cooler temps when I go to work at 2AM tomorrow. Hopefully my problem is fixed and I hope you have worked yours out as well.
Keep up the great work, Stangnet!
After searching these forums and finding this post with several suggestions, I started to check my grounds because I also noticed that my oil pressure gauge was running high and the needles would "wiggle" if I put a draw on the electrical system (ie: lighting up the brake lights or holding the power window switch down for an extra second once the window hit the travel stop). The grounds at the battery looked good and the engine to frame ground was solid as well.
In an attempt to solve this issue, I wired my own ground wire from the point where the hood ground strap is attached to the passenger-side fender to the rear bolt on the upper intake manifold. I test drove the car into town on some errands and once the engine was warmed up, the needle was between the O and the R with outside temps in the 93F+ range. I'll be able to report later what it reads in the cooler temps when I go to work at 2AM tomorrow. Hopefully my problem is fixed and I hope you have worked yours out as well.
Keep up the great work, Stangnet!
YEAHLOH95
Founding Member
I am going through a similar situation. The temp guage always used to read at the "O" no matter what. Lately, it bounces around from "O" to "A", and at that point the fan goes to high speed, and the temp goes down slightly, and the fan shuts off. I replaced the rad with a new unit because it was leaking from the tanks, hoping it would solve the temp swings, but had no effect on the temp. bouncing. BUT, if I leave the A/C on, forcing the fan to go to high speed, the temp stays pretty much back down at "O" all the time like it once did.
I haven't done much in the way of troubleshooting, but I believe the fan's slow speed isn't working any longer. What component controls the fan speed?
Also, can I just run a 12V wire to the low speed wire on the fan's wiring harness, and have the fan running on low speed all the time, or would this cause a conflict if/when the fan had to go up to high speed?
I'm not an electrician, so these may be dumb questions.
I haven't done much in the way of troubleshooting, but I believe the fan's slow speed isn't working any longer. What component controls the fan speed?
Also, can I just run a 12V wire to the low speed wire on the fan's wiring harness, and have the fan running on low speed all the time, or would this cause a conflict if/when the fan had to go up to high speed?
I'm not an electrician, so these may be dumb questions.
The low-speed fan-relay is commanded by the EEC.
As noted, you don't want to do the low speed modification, as having high and low both engaged at once is bad. You can do a high speed switch. You can also use a stand-alone thermoswitch to command high speed.
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