1998 C5 Radiator

[VantaR]

Hi everyone,

Apologies for the double post, I am reposting here because I think I may have put this in the wrong category/thread. Mods please remove my previous post if not allowed.

Just a quick one, although unfortunately I've got a bunch more questions coming

I'm getting a HIGH TRANS TEMP and LOW COOLANT warning on my 98 euro auto. Monitoring trans temps they seem to be fairly normal even when the warning comes up, and engine temps seem fairly normal too. Coolant level also normal (so figure it's a combination of a bad sensor and radiator) Steve has been very helpful and I think i need to start replacing things. Looks like my radiator is bent! Image Attached

So best to start there? What's the part number for a replacement radiator with the internal trans cooler? Ideally on rock auto if possible, I've seen two one with inverted flares (and after a quick google I still couldn't figure out the difference) I know the better solution is to run an external trans cooler, but I'm just trying to sort out all issues first and when cashflow allows I'll consider I dont track the car.

Thanks in advance!

 

[teamzr1]

If your 98 is the same as my 99
Low coolant sensor is in the bottom of the surge tank, look there and be sure the wiring connector is plugged in and that tank is clean at the bottom
Check wiring is good and not broken

Cannot tell in photo, where is the bent area, is it the end cap on right side as that is where the auto tranny fluid cooler is
The temp sensor is in the tranny
Have you checked that correct amount of auto tranny fluid, as low level would be hotter ?

What do you mean about some inverted flare ?

Here is a few at Amazon, switch it to the UK instead of here in the USA

Amazon.com : radiator

 

[VantaR]

Hi teamzr1,

Thanks for that and sorry for the delay, just had a quick look before it starts raining again!

Couldn't read the side of the tank but popped it open and it's definitely high enough. Maybe too high? Also I checked the sensor there on the right side of the picture, definitely connected, wires don't look or feel frayed at all. Is there any other way to verify that the sensor has gone bust other than replacing the whole tank? I dont think Rock auto sell the AC DELCO part anymore...




On the topic of radiators, it's this one here that says "inverted flare". I'd like to get the part from rock auto if possible, just cheaper on shipping. Which one would it be?

I had a look underneath the car, right side here. I cant see there's any issue with it? Also trans temps seem to be okay, climbs to 200F sitting in traffic but fairly normal I imagine.


Thanks again!!

 

[teamzr1]

Your surge tank is filthy and overfilled
Should look like this
Coolant level should be below the black top, there is a full line on end facing the front of C5
Overfilled is not allowing coolant and air to expand and could cause a radiator problem




The low coolant sensor is a floating magnet type and if coolant is mucky maybe causing the magnet to be stuck downward causing
Need to do a good cleaning, I suggest you get some coolant flush product you put in coolant and follows its instructions on engine running time
and then flush out and make sure surge tank is clean inside and out
At bottom right side of radiator is a drain valve to drain the old crap out

Look inside and make sure where sensor is, is clean
Close valve and fill with 50/50 percent water and anti-freeze
Then run engine at idle to allow flow and if any air pockets

Auto tranny cannot run cooler than the coolant is which the engine has a 195F degree Tstat so 200-230 F is normal

When I tune the PCM, I have owner put in like a 180 Tstat and in the PCM I tune the fans commanded on at 180 deg

I suggest due to C5 age is also flush and replace tranny fluid
at the least, check fluid level is not low

Cannot see what Rockauto parts are, as you need instead to post that Rickauto URL to where you were at

Lastly, flush the outside of the radiator and A/C condenser by using a garden hose and flush out all crap like leaves and other crap off
that reduces airflow

At this time I say do not replace radiator until all the above is done and also check the coolant fans function OK

 

[VantaR]

Thank you,

Yes, it does look nasty. I will get it flushed out and replaced with orange dexcool or whatever I can get my hands on. Does it particularly matter what goes into it? As long as it's fully flushed it shouldn't clog the system right?

I'm trying to get as many jobs ticked off the list. I'll hold fire on the radiator for now.

Just 3 more quick unrelated questions if that's okay?? Sorry to hijack the thread

1. Am changing my TPMS for my 98 euro. gauges show that FRONT L has no reading, Front R has a reading, and both back have no reading. I didn't notice the back two so I've only bought 1 x AC DELCO 20807214. My car fob also doesn't work but I just want to verify it's definitely a sensor issue and not a receiver issue.. If the front R is displaying, does that mean receiver is okay? Would there be any harm in going through the learning sequence and trying to calibrate FRONT R first (as FRONT L isn't installed yet) just to see if it'll horn / receiver is okay? I want to check because I'm fairly sure a 98 receiver unit is difficult to find so most upgrade everything to the 01-04 system, and I want to avoid that if possible.
2. I'm replacing my harmonic balancer, and don't need anything fancy as I'm not planning on supercharging. I've been looking at the DAYCO PB1117N. Enough good reviews and ToysForLife C5 on YouTube uses one, have you heard anything bad about that balancer? Obviously most will learn towards something more premium like an ATI or Summit unit, but I don't plan on adding power.
3. My middle air damn is missing, I have the two corner pieces attached. OEM is unnecessarily expensive, i see VetteNuts and TopFlightAutomotive selling them. Are either any good?

Thank you again!!!

 

[teamzr1]

Thank you,
My response is in red, Your Welcome

Yes, it does look nasty. I will get it flushed out and replaced with orange dexcool or whatever I can get my hands on. Does it particularly matter what goes into it? As long as it's fully flushed it shouldn't clog the system right?

Only buy Anti-Freeze that says is meets GM's Dexcool specs as it was designed for your radiator that is aluminum

I'm trying to get as many jobs ticked off the list. I'll hold fire on the radiator for now.

Just 3 more quick unrelated questions if that's okay?? Sorry to hijack the thread

1. Am changing my TPMS for my 98 euro. gauges show that FRONT L has no reading, Front R has a reading, and both back have no reading. I didn't notice the back two so I've only bought 1 x AC DELCO 20807214. My car fob also doesn't work but I just want to verify it's definitely a sensor issue and not a receiver issue.. If the front R is displaying, does that mean receiver is okay? Would there be any harm in going through the learning sequence and trying to calibrate FRONT R first (as FRONT L isn't installed yet) just to see if it'll horn / receiver is okay? I want to check because I'm fairly sure a 98 receiver unit is difficult to find so most upgrade everything to the 01-04 system, and I want to avoid that if possible.

For EU spec'd, assure what you buy the 433 Mhz version and not the lower 333 Mhz used in the USA
Are you sure the key FOBs battery are good, C5 came with 2 FOBs,
did you try both, need the early C5 ones ?

1. I'm replacing my harmonic balancer, and don't need anything fancy as I'm not planning on supercharging. I've been looking at the DAYCO PB1117N. Enough good reviews and ToysForLife C5 on YouTube uses one, have you heard anything bad about that balancer? Obviously most will learn towards something more premium like an ATI or Summit unit, but I don't plan on adding power.

Keep in mind the balancer bolt is torque to yield so it cannot be reused, and you need a new
Since that bolt is long to replace, it requires you lowering and moving the steering rack out of the way

If you do not do this right and the balancer gets loose will be a big problem, and you have to replace the bolt again
Have no idea about the one you mention, as I always have used an OEM one

1. My middle air damn is missing, I have the two corner pieces attached. OEM is unnecessarily expensive, i see VetteNuts and TopFlightAutomotive selling them. Are either any good?

Thank you again!!!

You need to get that replaced as it has 2 functions,
1 is to direct oncoming airflow to radiator and second
that dam reduces air getting under the car and causing front end lift at speed

Never heard of the ones you have seen but make sure it has the springs as that is what saves the dam when hitting low objects by
springing dam to pivot ad than spring back to correct position

 

[VantaR]

Thanks again, very useful stuff here

Understood, dexcool orange is what's in the car, i'll flush and use the same again

Yes the part I got is for a 433.92mhz TPMS which is for my euro spec. Previous owner only gave me the one fob and I changed the battery, still nothing when I tried to relearn the fob on the DIC. on the DIC the front R TPMS is the only one that is showing. Can I run the re-learning sequence (using the front R as the first one) with a strong magnet to verify that the receiver is still good before I go ahead and try get a new fob & the other TPMS? Is there any harm in that?

the Powerbond one is here: More Information for DAYCO PB1117N

People on forums and this channel here:

seem to favour it over the OEM, as it's designed the same way except the rubber is bonded rather than pressed. Would you still prefer OEM? And yes, i've picked up an ARP 234-2503 bolt as a replacement, will make sure I bin the old bolt.

Bar Amazon (they won't ship to the UK unfortunately) is there anybody else you'd recommend I get a front air dam from? The ones from VetteNuts or TopFlight have springs too, but just seeing is there's somewhere better to get it from?

 

[VantaR]

Actually to correct myself:

This part here from Amazon DOES ship to the UK:

https://www.amazon.com/Corvette-Complete-Compatible-Replacement-845616-1/dp/B0CBTGPDXW?crid=3IWPJKBKFLC02&dib=eyJ2IjoiMSJ9.mSZbk2ER57nGc4vu7kSrIIsNRmsLTq6LiK2N6kzKZq0VDP_c5OKhXKoQhH107NJYI-zGtVhR-3u8Hs0hzOZJZRUqtB8C-f70ZW5-cVtft0YwlAnKpdgmIXcGvTuldnEbqQIII6TxK4W639Hh8dDGvKdz5AsSne8Jtk2vczsHcfTdUKnGQ-N24ruPRrXfMB8pvV_U6ahZnsYK-AHPjfkyKIgbpR0YA2Q2Ud9eCkBALyo.7zN-pz_MFnI4xAcnh3GyL9aoLNyXgrYnBzwK6V4h49U&dib_tag=se&keywords=c5+corvette+front+lower+spoiler+air+dam&qid=1735922811&sprefix=C5+Corvette+Front+Lower+Spoiler+Air+Dam%2Caps%2C445&sr=8-1

teamzr1, is this the right part? It has the springs too.

 

[teamzr1]

Actually to correct myself:

This part here from Amazon DOES ship to the UK:

https://www.amazon.com/Corvette-Complete-Compatible-Replacement-845616-1/dp/B0CBTGPDXW?crid=3IWPJKBKFLC02&dib=eyJ2IjoiMSJ9.mSZbk2ER57nGc4vu7kSrIIsNRmsLTq6LiK2N6kzKZq0VDP_c5OKhXKoQhH107NJYI-zGtVhR-3u8Hs0hzOZJZRUqtB8C-f70ZW5-cVtft0YwlAnKpdgmIXcGvTuldnEbqQIII6TxK4W639Hh8dDGvKdz5AsSne8Jtk2vczsHcfTdUKnGQ-N24ruPRrXfMB8pvV_U6ahZnsYK-AHPjfkyKIgbpR0YA2Q2Ud9eCkBALyo.7zN-pz_MFnI4xAcnh3GyL9aoLNyXgrYnBzwK6V4h49U&dib_tag=se&keywords=c5+corvette+front+lower+spoiler+air+dam&qid=1735922811&sprefix=C5+Corvette+Front+Lower+Spoiler+Air+Dam%2Caps%2C445&sr=8-1

teamzr1, is this the right part? It has the springs too.

Yes that is the set and at cheap price
Should help to flow cooler air through radiator opening

 

[teamzr1]

Since I have only used stock dampers, I cannot give a viewpoint on other types
If not adding any type of boost to engine, you do not need any fancy high-priced ones

Also note to properly torque down that new TTY bolt you need to be able to lockdown the flex wheel for auto tranny (flywheel for manual tranny)
One choice is to remove the starter and buy or make a tool that bolts in place of the starter and has teeth that match the flexwheel

I had none at the time so made one



I suggest you go back to owner's manual for the step-by-step instructions using the DIC to relearn that FOB
Maybe the one you have is not the original one and need to get yours sync'd to the car

As to TPMS, yes you could use a Earth magnet and via DIC relearn each new sensor after you replaced all 4
or the place you take the car to swap to the new ones would have an electronic tool to pair and learn them to the C5

Thanks again, very useful stuff here

Understood, dexcool orange is what's in the car, i'll flush and use the same again

Yes the part I got is for a 433.92mhz TPMS which is for my euro spec. Previous owner only gave me the one fob and I changed the battery, still nothing when I tried to relearn the fob on the DIC. on the DIC the front R TPMS is the only one that is showing. Can I run the re-learning sequence (using the front R as the first one) with a strong magnet to verify that the receiver is still good before I go ahead and try get a new fob & the other TPMS? Is there any harm in that?

the Powerbond one is here: More Information for DAYCO PB1117N

People on forums and this channel here:

seem to favour it over the OEM, as it's designed the same way except the rubber is bonded rather than pressed. Would you still prefer OEM? And yes, i've picked up an ARP 234-2503 bolt as a replacement, will make sure I bin the old bolt.

Bar Amazon (they won't ship to the UK unfortunately) is there anybody else you'd recommend I get a front air dam from? The ones from VetteNuts or TopFlight have springs too, but just seeing is there's somewhere better to get it from?

 

[VantaR]

Thank you,

I've bought the air dam, phew that's one off the list!

Yes, i've seen some similar looking tools to that, i've seen one that I think you also don't need to remove the starter for too. Will just go for whichever closer to the time and stick to the OEM balancer.

Just before I buy the other two TPMS as they are about £100 each total from rockauto.. still all good for me to to try and relearn just the FRONT R one (only one showing as working) just to verify that the receiver isn't bad? Would feel a waste to buy the next two and then find out receiver has gone bad...

 

[teamzr1]

Thank you,

I've bought the air dam, phew that's one off the list!

Yes, i've seen some similar looking tools to that, i've seen one that I think you also don't need to remove the starter for too. Will just go for whichever closer to the time and stick to the OEM balancer.

Just before I buy the other two TPMS as they are about £100 each total from rockauto.. still all good for me to to try and relearn just the FRONT R one (only one showing as working) just to verify that the receiver isn't bad? Would feel a waste to buy the next two and then find out receiver has gone bad...

If the serpentine belt is old, this would be a good time when replacing the damper to replace it

If you have a decent OBD-2 scanner, and it supports the remote controller which handles the TPMS and key FOB
and see if the scanner can connect to that controller and if it does, that says at least the controller is talking
As my scanner does you see for a C5 each wheel sensor's status and reported tire PSI from the sensor
If no scanner, if you know soneone with a GM tech2 diag tool would work

This would help to know controller is good and functional



That controller is mounted in the B-pillar on the driver's side
From the left side of the hatch, pull the carpet back and look between the B-pillar and the inside panel that covers where the mount for seat belt and targa top is
Make sure the fuse for controller is good, check the wiring connector is plugged in and the antenna wires and ground are good

 

[VantaR]

Hi!

Gotcha, okay I'll inspect the belts for wear and the pulleys for any wobble of sorts

Unfortunately no OBD tool, and no, don't know anybody with the other tool. Just as a poor man's way of investigating. Say if one of the readings is showing (image here) would that mean that the receiver is working? Or could it possibly show up a value even if the receiver is bust?

 

[teamzr1]

Do a test with the one working, right front shows 28 PSI (196 Kpa)
Add some air, like 5 PSI and see if DIC than shows correct reading by little drive

IF so, that means the remote controller is working and the other 3 TPMS are dead

Also, could well be your FOB does not work, or not corrected paired/sync's with the car

 

[VantaR]

Ah great! Phew! Was hoping to hear that I could do something like that So fill it up and then go for a short drive, gotcha. Any specified amount of time or does the system figure out fairly quickly?

 

[teamzr1]

Depends on the weather, maybe couple of miles driven

 

[monkaw14]

Hi everyone,

Apologies for the double post, I am reposting here because I think I may have put this in the wrong category/thread. Mods please remove my previous post if not allowed.

Just a quick one, although unfortunately I've got a bunch more questions coming

I'm getting a HIGH TRANS TEMP and LOW COOLANT warning on my 98 euro auto. Monitoring trans temps they seem to be fairly normal even when the warning comes up, and engine temps seem fairly normal too. Coolant level also normal (so figure it's a combination of a bad sensor and radiator) Steve has been very helpful and I think i need to start replacing things. Looks like my radiator is bent! Image Attached

So best to start there? What's the part number for a replacement radiator with the internal trans cooler? Ideally on rock auto if possible, I've seen two one with inverted flares (and after a quick google I still couldn't figure out the difference) I know the better solution is to run an external trans cooler, but I'm just trying to sort out all issues first and when cashflow allows I'll consider I dont track the car.

Thanks in advance!


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Sounds like the bent radiator could be the culprit! Start by replacing it—check Rock Auto for one with an internal trans cooler (verify flare type). Fixing this should help, and you can always add an external cooler later if needed. Good luck!