Cooling Issues

[SHOpar]

The SHO I am working on right now that has a leak coming out of one of the coolant tubes also seems to run a bit warm according to the gauge. It'll go all the way up to the "O" before the fan will kick on, and then it'll drop down about half way, and start traveling back up when the fan turns off. If the A/C compressor is running (in defrost mode)and the fan is always on, the temp stays down between the "M" and the "A".

I know the dash gauge is notoriously inaccurate, but the temp still shouldn't be spiking. We did a full 60K on this car six months ago, including a new thermostat and sending unit for the gauge. I believe we also replaced the sending unit for the computer, but I'll have to check.

Any recommendations? The coolant leak is pretty substantial, so could this be causing pressure issues and the temp spikes? My Omni had this problem forever until I finally had no more heat. After flushing the heater core, the temp spikes went away completely and the heater will blast you out of the car!

 

[89 black SHO mtx]

how long does it take the temp to spike is it a normal climb or a quick one??? it could very well be a temp sensor, but if your losing that much coolant that could be it as well get the leak fixed first then see what happens

 

[sdpatt]

The spikes you refer to could be normal if there is not sufficient airflow through the radiator to remove the heat. Like when the car is sitting still in traffic or in the garage. It looks like you installed a 190 degree thermostat in place of the 180 degree version that the 3.0L was originally supplied with. It also appears that the fan start temp is higher than others with the 3.0L engine. I have usually seen the fan to start when the temp gauge reaches the "M-A" range on the gauge in my car.

The position on the gauge is meaningful only when you know what the true temperature is that corresponds with the gauge position. Measure the temperature at the thermostat housing both upstream and downstream of the thermostat to see what temperatures you are really operating at. This will also show you at which temp the thermostat is actually opening.

A reduction in pressure will cause a reduction in cooling capacity from the localized boiling in the engine. Which "coolant tube" is leaking?

 

[SHOZ123]

When the car has cooled from sitting over night and you take the radiator cap off, is the radiator completly full?

 

[SHOpar]

sdpatt:
A reduction in pressure will cause a reduction in cooling capacity from the localized boiling in the engine. Which "coolant tube" is leaking?

The coolant tube where the CELO sensor plugs in for the EATC.

I'm pretty sure it's just the rubber hose and crimped connector that is leaking, but I am going to try to replace the whole tube if I can.

When we did the 60K, the parts were purchased from SP Motorsports, so I am sure they sent us the proper thermostat.

I might end up ordering a new thermostat and both coolant sensors just to rule these out. I don't think airflow to the radiator is blocked, as the car is maintained quite well, had a new radiator installed by the dealer about three years ago and a new fan installed about a year ago after it took a dump.

 

[SHOpar]

SHOZ123:
When the car has cooled from sitting over night and you take the radiator cap off, is the radiator completly full?

I haven't checked, but likely not, as the coolant tube generally starts leaking more right after shutting the car down. While running, the leak slows quite a bit.

<small>[ March 20, 2003, 05:05 PM: Message edited by: SHOpar ]</small>

 

[oh_SHO]

I am having the same type of problem with out the coolant leak. It never used to do this until last summer. The temp stays normal when I am moving along but as soon as I drop below 35 and the outside temp is above 30 it runs hot. When its above 60 outside the fans won't bring it back down. I am about to do my 60K with a new water pump and a thermostat. Anything else I should look for while I am digging around in there? Current t-stat @ 1.5 years and rad. @ 3 years (I think).

 

[SHOZ123]

SHOpar:
I haven't checked, but likely not, as the coolant tube generally starts leaking more right after shutting the car down. While running, the leak slows quite a bit.

If the coolant is not completely full up the neck of the radiator cap area then there is air in the system. This will make the temp swing.

If it is just the rubber hose that is crimped cut it off. You can replace all but the U shaped oil cooler hose with bulk hose.

<small>[ March 21, 2003, 01:36 AM: Message edited by: SHOZ123 ]</small>

 

[SHOpar]

Well I FINALLY got the coolant tubes off to replace the crimped-on hoses on the engine side of these tubes. Talk about a PITA! The easiest part was cutting the crimped fittings off, which I was thinking was going to be the most difficult part!

The bolt that secures one of these tubes to the back of the head is so difficult to get to I finally had to go out and buy a 13mm crow's foot to get the thing off after trying everything I could think of for two hours. Even after breaking it loose, I could only turn the bolt 1/4 turn at a time with a wrench, since there was no clearance to get a socket on there. Simply removing these tubes took me all afternoon! I can't remember when the last time I was so angry at a car!

I also found out about 6 pm tonight that one tube uses 5/8" inch hose and the other uses 3/4". I had only bought 3/4". Not a big deal, except EVERY autoparts store around closes at six on Sundays. Luckily I found ONE store that's open 24 hours and I was able to get the hose - one nice thing about being in Portland (I can't wait to move here!)! thumbs_u

I lost all motivation to finish it tonight though, so I'll start fresh in the morning. And to think, this isn't even my car. I am just helping a friend of mine who is on vacation with his girlfriend for a week.