Dennyj1992

Before anyone flames, yes I've used the search bar and looked into this. Still having trouble getting answers. Just a few things here I'll start with.

First off, my coolant temp gauge never moves from 100 degrees. Not when hot, cold, sitting or running. Never moves, at all. I've been told this may be the CTS? If so, I'm at a realization that the certain part is cheap and would be glad to fix this first. However, where is it located? Does anyone possibly have any pictures to help with that?

Second, I filled up my coolant the other day and while I'm having a bit trouble reading these fill levels, (used to "low" and "full" readings) I may have overfilled it. My car was dumping coolant out of the cap when warm and when I pulled it off, it spat out a bunch more and doesn't overfill or dump anymore out. Must of overfilled. Any other suggestions to what could of made it do that? Before when I shut it off, the upper radiator line was gurgling, to say the least and it seemed like I may have some air in my lines.

By the way, I'm not sure if this helps at all with this little adventure but the car doesn't blow heat very well nor at a high rate. The engine gets warm (can tell from under the hood, not from the gauge since it doesn't work). However, it doesn't smoke or anything like that (besides when coolant came out and poured all over the engine and what not). My exhaust smoke is not any more white than it should be for a Michigan November. To top it all off, not a drop of coolant in my oil...it's solid. Engine doesn't tick or knock either.

The car is a 1993 3.4, automatic, if that helps too.

Dennyj1992

Just to add a bit more information here, if it brings anymore enlightenment to anyone. My fans kick on right as I start the car. Hope that helps too.

Dennyj1992

Hhhhmmm...seems I've gotten no help from anyone. Have the forums become slow or just quiet around here? Haha.

Anyways, the car is fixed based on the cooling issues now. System was bled today, the new CTS was put in, along with a new T-Stat as well. Car runs great and fans don't come on right away. It also sits at 1/4 on the coolant temp gauge even when it's been sitting.

Injuneer

V6 tech is very "slow". I'd help more, but I don't know anything at all about the 3.4L, so the help will be limited.

Looking at the 93 factory manual, the coolant temp sensor for the gauge is on the drivers side head, front of engine, near the ICM/coil assembly, and behind what appears to be the power steering reservoir. The temp sensor is a thermistor - resistance is inversely proportional to temperature - high resistance = low temp; low resistance = high temp. Since your gauge is pinned at the low temp, it would indicate an open circuit (infinite resistance). The single wire may be off the sensor or the sensor may be faulty. Shoebox has a procedure for testing the sensor:

4th Gen LT1 F-body Tech Articles

For the overflowing radiator, check the performance of the radiator cap. It has to hold pressure (typically 16-18psi, I don't know the specifics of the 3.4L). The pressure is required to prevent the coolant from boiling (so is a 50/50 mixture of coolant). Boiling coolant will make the "gurgling" sound. If the cap isn't holding pressure it will boil over. Could also be a head gasket, but let's not go there yet.

You should insure that you have filled the coolant all the way to the very top of the radiator fill neck, and that all the air is out of the system. Don't rely on the level dipstick in the reservoir. The radiator should always be full to the top. When the coolant heats up, and expands, some of it will flow into the reservoir. When the coolant cools down and contracts, the resulting vacuum will pull the coolant out of the reservoir, back into the radiator to keep it full to the top. If you check the level in the radiator and frequently find it down an inch or two, you may have a crack in the rubber hose from the fill neck overflow to the reservoir. If that hose is cracked, the vacuum can't pull coolant back into the radiator.

When the engine is hot, check the heater supply and return lines to see if they are hot. If they are not hot, the heater core may be plugged up - a common problem in the 4th Gens, particularly now that these cars are 20 years old. The heater core can be flushed by pulling the hoses off at the water pump end, and flushing water through them with a garden hose.

Dennyj1992

Well like I said before, I drove it to my shop yesterday and sat there while they worked on it for a four hours.

Since I didn't realize I wasn't supposed to leave the CTS out it was smoking and pouring coolant by the time we got there, only 3-4 miles away. He politely asked me to never do that again, since he didn't wanna see a LIM gasket or head blow out.

My mechanic did a head gasket check right after that and it checked out fine. Also put in a new thermostat and the right CTS. Car doesn't go above 1/4 on the coolant gauge now and runs cold. Heat also blows hot out of the vents. While he was at it he changed the tranny mount since it was completely busted and sitting on top of the exhaust, making it rattle.

Car runs great now and I'm going to pick it up on Monday, since I need to title and plate it. SoS is closed today so I'll have to wait until then. Total cost came out to only $165...he gave me a really good deal, considering he used 2 gallons of coolant to top it off (yes it was that low, lol). He actually did about $350 worth of work!

Again, thank you for the help and having the only useful response!

Can't wait to hit the road with her next week!

Injuneer

Do you mean you unscrewed the coolant temp sensor and then drove the car with an open hole in the coolant system? You do realize you blew all the coolant out of the system, hence the need for 2 gallons of coolant. You do realize that the coolant isn't that expensive?

Engine shouldn't run "cold".... if the coolant doesn't get hot enough, the PCM will not go into closed loop, to correctly control the air/fuel ratio. Could also cause water condensate to build up in the oil, since it will never get hot enough to drive off the condensation. The engine was designed to run at the midpoint of the gauge, which is about 210*F. If the gauge basically never moves from the 1/4 mark, even after the car has sat long enough for the engine to cool down, you still have a problem with the coolant temp sensor or the gauge.

Which coolant temp sensor did you remove - there are two - one in the driver side head for the gauge, and one under the front/center of the intake plenum for the PCM? Which sensor did the mechanic replace?

Dennyj1992

The CTS behind the power steering pump reservoir was replaced. Yes, I drove it without it in to the mechanic's shop. That was my bad. The part itself was only around $10 but was easy to change. Just took a minute to find out a way to screw the damn thing in. The threads were difficult to line up is all.

The car sits at 1/4 if I'm driving it but does go up a bit if the car is sitting, then flushes once I start driving it again. Coolant was $15 a gallon for my mechanic but he only charged my $10, which was only $2 more than was O Reily's charged me at $8 a gallon. Not bad at all, if you ask me.

It runs great now and doesn't run hot, smoke, or leak anything at all. Just test drove it today too. The new tranny mount helps shift the car great and the exhaust doesn't rattle either.

Any other suggestions on this? Seems to cruise around town just fine? I'm pretty sure that the problem is solved.

Now on to to a few more things to work on..

(Thanks guys!)