...oddly enough the radiator fan was on, even though the gauge showed such a low temperature.
...there's a huge difference between the sensors for the temperature gauge and the radiator fan.
The fan switch is located at the thermostat end of the intake, and the temp sender is at the opposite end of the motor in the rear head. Since both the temp sender and the fan switch get their readings from being immersed in coolant, it would seem the only explanation is that there is a difference in coolant temperature between the two locations. However, it's difficult to imagine that there could be such a difference in the coolant temperature itself within the engine. Is it possible then that travelling air pockets/bubbles are responsible due to them passing by the temp sender or fan switch and temporarily throwing off the readings?
Cliff sorry I’m late to this thread , if I wasn’t late parts stores do carry adapters for male to female , for transmission lines but I see you already cut them to run rubber hose which is fine ,,, the radiator fan ,, I’d do Kyle fan mod , I did it on my car and man huge improvement, also I recommend Rodney’s 190 fan switch and 180 thermostat
The fan switch is located at the thermostat end of the intake, and the temp sender is at the opposite end of the motor in the rear head.
I'm starting to think that the temperature gauge sending unit might be faulty. I think the fan switch is working correctly because it doesn't turn on during very short trips, even if my temperature gauge shows that my engine is overheating. When I ignore what the temperature gauge is showing, the cooling fan turns on and off at the times I expect it to. However, the temperature gauge is acting highly erratic.
Furthermore, after driving for a long 1.5-hour trip on the highway and then driving at a slower speed of 30mph for 15 minutes, it doesn't make sense that the temperature gauge shows a reading of 135°F while the radiator fan is running. The radiator fan running is expected, but an engine temperature of 135°F is not. Even if there was a trapped air bubble at the temperature gauge sending unit, the air temperature there should be near the temperature needed to trigger the fan switch.
So, my plan is to first replace the temperature gauge sending unit before I go any further in trying to figure out this issue.
I've read in several threads now that the way people check if the waterpump is working, is by removing the tstat housing cap, as well as the thermostat, then start the engine. And that you should see a steady flow of coolant running.
If I do that (with a cold engine), it's more like a fountain. Coolant sprays out with brute force.
I've read in several threads now that the way people check if the waterpump is working, is by removing the tstat housing cap, as well as the thermostat, then start the engine. And that you should see a steady flow of coolant running.
With a conventional engine setup (where the radiator cap is the high point of the system), removing the rad cap would allow the observation of coolant flowing in the radiator... but I kind of doubt that removing the thermostat cap and thermostat would allow a similar view of gently flowing coolant... unless perhaps the coolant level was low enough to easily allow coolant flow into that large hose at the housing?
Cannot Trust Dash Gauges/Meters! They Lie and often for just wire from X meter to Y sender even when both work then add often have iffy power and grounds. Just 1 Example: https://www.fiero.nl/forum/Forum2/HTML/146784.html
Get a ECM scanner or maybe other methods to watch engine temp.
Note: IR tools including "FLIR" cameras are not very good for this problem. K type thermal couple or 100KΩ thermistor attach to T-stat tube base maybe read this accurately enough.
Cannot Trust Dash Gauges/Meters! They Lie and often for just wire from X meter to Y sender even when both work then add often have iffy power and grounds.
A few months ago, I replaced the dash and that didn't make a difference. So I know at least the problem is not in there.
I'm starting to think that the temperature gauge sending unit might be faulty. I think the fan switch is working correctly because it doesn't turn on during very short trips, even if my temperature gauge shows that my engine is overheating. When I ignore what the temperature gauge is showing, the cooling fan turns on and off at the times I expect it to. However, the temperature gauge is acting highly erratic.
Furthermore, after driving for a long 1.5-hour trip on the highway and then driving at a slower speed of 30mph for 15 minutes, it doesn't make sense that the temperature gauge shows a reading of 135°F while the radiator fan is running. The radiator fan running is expected, but an engine temperature of 135°F is not. Even if there was a trapped air bubble at the temperature gauge sending unit, the air temperature there should be near the temperature needed to trigger the fan switch.
So, my plan is to first replace the temperature gauge sending unit before I go any further in trying to figure out this issue.
If it really does go up into and beyond the red on the gauge you'd have the coolant reservoir erupting and spewing coolant everywhere. I wouldn't trust the gauge at all. Drive it like you don't have a temp gauge. Its not the end of the world if you overheat it. The iron head/iron block 2.8 doesn't blow headgaskets easily, though you could be unlucky. On an old Fiero I had, the waterpump failed and I had it overheat 4-5 times spewing out the reservoir and it was fine for years after I replaced the pump.
If your gauge IS accurate I'd say its reading air pockets/steam that passes through the system. You can only bleed it so much and hope for the best. These systems generally bleed themselves out given enough time.
I'd still track down what's bad between the sensor, wiring, and gauge. Maybe wire up an aftermarket gauge and see what it does? Not sure if I read that you did that, the story of this has spanned a few threads at this point.
Hi Cliff. If you can borrow a radiator test pump/pressure gauge and pressure the system with it to 10 psi and watch the gauge for a couple of minutes. If it doesn't drop then start the engine and let it idle. If the pressure slowly climbs it is probably ok. If it starts climbing rapidly then you may have a problem that will hurt your engine and definitely further checks will be necessary. Your engine should never spew coolant out the thermostat hosing with the thermostat removed. It should just circulate as the water pump pulls in as much as it discharges. sleek
I've tried to find a coolant flow diagram of the V6 but were unable to find one (other than a very, very basic one). So I looked at the service manual an now I'm even more confused.
Looking at this picture:
that tells me hot coolant from the engine travels the pipes on the passenger's side of the car to the front of the car. And that cooled coolant travels the pipes from the radiator to the engine on the driver's side of the car.
But then I look at this picture of the radiator:
It says the inlet tank is on the driver's side, and the outlet tank on the passenger's side. So hot coolant is coming in on the driver's side en cooled coolant is coming out on the passenger side - which is completely the opposite of the first drawing. Or do they mean that the inlet tank is actually the radiator's outlet tank but is connected to the inlet pipe of the engine? I'm confused.
I can see why the confusion, but if you think of both pictures in terms of the radiator they make sense. The thermostat controls flow out of the engine, and it allows hot coolant to run through the pipe on the driver's side, into the inlet tank on the driver's side of the radiator. The water pump pulls cool coolant from the passenger side of the radiator and pipe and pushes it into the block. To simplify hot to the radiator on the drivers side and cold from the radiator on the passenger's side. Rick
As for the transmission lines, which of the two is the inlet (on the radiator)? The upper or the lower?
Also, looking at the design, you can clearly see that it's designed to keep the transmission oil temperature at engine temperature. And not to cool it. If that's the case, why would you want to introduce a transmission oil cooler in the system? That defeats the design of the cooling system.
Originally posted by Cliff Pennock: A few months ago, I replaced the dash and that didn't make a difference. So I know at least the problem is not in there.
Does Not = this dash is any good or even same as old unit. Even a brand new dash put in a 30+ year old car can have big problems. Gauge Senders ground to body etc & 1 Iffy ground connection anywhere can make gauges lie. Iffy Power connection can do same.
Is Why ECM have Regulated 5V &or Ground to almost all sensors. Only "1 wire" O2 "grounds" thru the exhaust.
My Temp Gauge reads Lower then ECM ECT because of same problem somewhere in that wiring. But Fuel gauge is close to accurate now when cleaned the clips etc in link page. Cleaned the sender & connectors when replacing F-pump didn't help much even test for 0-90Ω on the sender & C502 connector w/ Ω meter.
OP gauge "pegs" and replace it & senderS & still "pegs" most of time even w/ Fix Resistor close to 45Ω (42 or 48) should be close to middle gauge range but "pegs" @ little over 80PSI.
"Bigger"/"Better" Rad often makes Temp Swinging "Worse" because cools down more in Cool/Cold Weather and slug the engine when T-stat opens fast. Depending where, how long, and more the engine temp may Never stabilize. Super stat may look same as OEM but had different temp curve to operate in & far less Temp Swings that "people" see as "a problem" when often is nothing. Even if you order by Stant PN, very likely only get "OEM" type since Motoraid buyout.
Many Big Trucks have Shutters in front of Rad to manually or auto close in cold weather for same reason. Even then some trucks still have covers over the grill for more protection in cold weather. Because those Huge radiators often needed in warm/hot weather but works against the engine in cold weather & can't make enough heat just to run right.
Yes, I understand the second dash could be iffy as well. But it didn't make any difference as far as the erratic temperatures were concerned. I've ordered another temp gauge sending unit but since it's shipped from the US, it might take a few weeks to arrive.
Hi Cliff . Yes you could have a bad gauge but it is more likely a bad sender. I replaced my sender and the gauge always was in the normal range but the idiot light was glowing after 5 minutes of driving .I changed it out with the Standard replacement unit and no more problems. I am sorry to say the 1st 0ne was from the Fiero store . Don't trust Chinese parts. sleek
Originally posted by Cliff Pennock: Yes, I understand the second dash could be iffy as well. But it didn't make any difference as far as the erratic temperatures were concerned. I've ordered another temp gauge sending unit but since it's shipped from the US, it might take a few weeks to arrive.
New sender may help, or not, for gauge that reads low.
E2A--> Because iffy wiring that add resistant or cause low volts make Temp gauge to lie because sender is NTC thermistor so less resistance = higher temp
[This message has been edited by theogre (edited 08-21-2023).]
Yes you could have a bad gauge but it is more likely a bad sender.
Which is why I ordered a new one. 😄
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Don't trust Chinese parts.
Not to sound stereotypical or anything, but it seems to me China can only produce "complete and utter crap" or "I can't believe they can make this for so little money".
Anyways, I have no idea what I will be getting but if it is the sending unit that is causing the problems, I should at least see some change with the new sending unit.
Mr ogre, it will fit the rad .I have one with a ton of adaptors for my work but as seen in pic will work no problem and it will eliminate possible causes of Cliffs problems. If [ was in the netherlands i would visit Cliff and solve this . But i am not so all I can do Is suggest solutions that I would use at work
Not to sound stereotypical or anything, but it seems to me China can only produce "complete and utter crap" or "I can't believe they can make this for so little money".
Good read. Lots of brainstorming in here, always good to have multiple takes on how to do something.
I'd just like to add my experience with Aliexpress. It's great for cheap things, but anything over 50 bucks I really try to avoid buying off Aliexpress. Ordered dozens of small things over the years, velcro rolls, magnets, arduino components, electrical components, led lights, brake parts for Honda trikes, carburetor and electrical for GY6 scooters, gun sling and ammo sleeve for a shotgun, "speed" nuts for the Fiero exhaust manifold shield, soldering materials, dremel attachments, computer parts, and tons of junk I didn't need but said "screw it, it's cheap enough!". Heck I even bought a phone off there, an iiiF150 R2022. A sister brand of Oukitel.
Majority of the stuff came in no problem, although sometimes you gotta wait a few extra weeks compared to amazon, but most of the time it's 30% cheaper for the exact same product. Only twice did I get the wrong part. Once I ordered 20 red 198 bulbs, and I got 10 red and 10 green. The inside of the bulb has an extremely similar orange color, so I can see how they grabbed the wrong ones. But I claimed full refund and got it right away. Second time I ordered an old 2012 CPU for my Acer laptop to upgrade it a little bit. 10 bucks to double the speed, so why not, maybe I'll use it more if it's faster. Ordered a 3 core cpu with I think 3 ghz, but got a 4 core at 2.3 ghz. Something like that. It was still better than my original single core 2 ghz, but it wasn't what I ordered and it's not as fast for general web browsing. Claimed a full refund and got that too, although I would taken a few bucks off as it was still usable.
Anyway, point is they sell things cheap, and you get cheap things. Glad it's mostly figured out now, but that's the kinda thing I'd expect from Aliexpress. Save a few bucks but you gotta screw around sometimes. They have less standards than Amazon sellers. Glad to hear you got a partial refund too, as it should be. So far Aliexpress has been great for me, Amazon as well actually, I guess I buy enough junk that they trust I'm not lying during claims.
I've ordered another temp gauge sending unit but since it's shipped from the US, it might take a few weeks to arrive.
And of course with my luck, they sent me the wrong one... I ordered the Delphi TS-10051, which is the correct one for the Fiero. The picture on their Amazon page even shows the correct one:
The box I got says it's the TS-10051. But inside the box...
Sensor, coolant temperature gauge and warning switch (HS125CM-12V printed on the body) GM 25036809 / AC Delco 213-71 / Standard Ignition TS-168 (Aftermarket: Delphi TS10051)
When I fixed the infamous "pegging" issue of the coolant temperature gauge, I installed a new Standard Ignition TS-168 Sensor. The original GM Sensor had the same HS125CM-12V printed on the body as the Standard Ignition TS-168 Sensor, however the 'new' Sensor had a lower reading on the gauge.
I have two links if you want to 'rewire' the "pegging" issue which the first link has a lot of information...........
Yes the TS 168 standard is the one I used . I also used a mechanical test gauge to check the accuracy of my dash gauge and they were very close over the whole sweep up to running temp. Hang in there Cliff . You will get it all straightened up. If you want Email me and I will grab you a standard TS 168 and send it to you by priority mail or FedEx seeing how I can't buy you a beer ! sleek
So last week I ordered the TS15001 from Walmart (because their website said they had it in stock and it was cheap), today I received an email they canceled my order because they do not have it in stock and apparently, it will not be restocked.
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Originally posted by sleek fiero:
Yes the TS 168 standard is the one I used . I also used a mechanical test gauge to check the accuracy of my dash gauge and they were very close over the whole sweep up to running temp. Hang in there Cliff . You will get it all straightened up. If you want Email me and I will grab you a standard TS 168 and send it to you by priority mail or FedEx seeing how I can't buy you a beer ! sleek
I'm going to try to order it from Summit Racing first; if for any reason that fails too, I might take you up on your offer! Thanks!
I'm going to try to order it from Summit Racing first...
I don't know how well the shipping fee (including brokerage etc) from Summit Racing compares, but in my experience, RockAuto's shipping fee to an international location can't be beat.
I'm not sure why you're focusing on the Delphi sender, but This is the one I'd order.
I'll add, that when you get the new sender, do not use teflon tape on the threads. I would use plumbers' compound. The Teflon can insulate the body of the sender from ground. You're more likely to get a good connection through the plumbers compound.
I don't know how well the shipping fee (including brokerage etc) from Summit Racing compares, but in my experience, RockAuto's shipping fee to an international location can't be beat.
Yes, I suddenly realized that whilst I was checking out on the Summit site. I buy all my "small" parts from RockAuto and their shipping costs have always been more than reasonable. So I'm not sure why I hadn't checked them first. Fortunately I hadn't finalized my order at Summit yet, so I was able to check out the prices @ RockAuto.
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I'm not sure why you're focusing on the Delphi sender, but This is the one I'd order.
At RockAuto, I was actually planning on ordering the TS 168.
At RockAuto, I was actually planning on ordering the TS 168.
Would yours be a better choice?
I've had a few Wells components that seemed like decent quality... but no, I think they're probably equivalent. And they're the same price, so flip a coin and pick one.
Perhaps you didn't noticed Cliff, however I posted:
The original GM 25036809 Sensor has the same HS125CM-12V printed on the body as the Standard Ignition TS-168 Sensor.
I suggest the Standard Ignition TS-168 Sensor over other aftermarket brands like Delphi TS10051.
Plus is very important as Raydar also said; Do Not Use 'Sealing Tape' (Teflon tape) on the Sensor Threads - the Sensor Threads Connects 'Ground' to the Engine.
I used high temp RTV; Raydar likes plumbers' compound.
Locktite has a liquid Teflon that is meant for automotive / industrial use that lubricates and seals and does not harden. Teflon tape and plumbers paste are just that -----meant for plumbing. The Locktight product is good for oil , antifreeze and air and works in extremes of temperature. it also allows for electrical conductivity. sleek
