Coolant and overheating

[aeo]

The truck has been running great. Has a new crate 300tdi in it. Had a bunch on hiccups on the instal but now is solid. Today driving back into town it overheated. Turned on the heat- it was tepid at best. Not really even warm. Pulled over, steam from around the radiator. Opened the cap on the overflow tank, bubbled out, settled down. Steam stopped and then added some coolant to the over flow tank and drive the last few miles home- temp fine. Some coolant on the grill and some drops on the ground when I parked it. My initial thought was the head gasket- but I had no loss of power, normal EGT, and no smoke.

EGT was normal, oil pressure normal, boost normal, no smoke, truck was cruising along fine and Iooked down and saw the temp gauge (stock) in the red. Truck has a upgraded turbo, Ali sport radiator and oil cooler, boost pin, and I believe the pistons were bored out a bit from a mishap with a metal shaving when the motor was installed. I am looking for the emails about that- it’s been two years since the engine instal was started. Motor has been in the truck for a year. Just installed a new alternator and stopped the fuel return lines from leaking. They were worn and stretched out.

Normally I only drive a few miles in town and this is the weekly drive out of town that is faster.

Thoughts? Opinions? Ideas?

Thanks,
Alex

 

[jymmiejamz]

My head gasket blew a couple of weeks ago. I was cruising on a back road at 60 mph when the temp shot up. No external leaks other than from the expansion tank cap. Did a leak down test and found it blown on cylinder #2. Replaced the gasket with a Genuine MLS gasket and drove it to Colorado the next day. I did not have any loss of power or smoke, also no warning signs.

 

[MountainD]

The heat blowing out tepid makes me also suspect coolant flow issue. Wether radiator, thermostat, air pocket…. I’d start with head gasket test, but always a suspect to me when coolant is steaming hot without heat at box/vent.

 

[javelinadave]

As I read the OP's post an air pocket was the first thing that came to mind. When you fill up a 300Tdi you really need to jack up the front end or top it off on a steep incline.

 

[aeo]

The weird thing to me was that within a few minutes of taking the cap off the expansion tank the steam from the radiator stopped, like it was able to cool off. Which makes me think coolant flow issue also.

 

[javelinadave]

Fill it up, crank it up, let it warm up and see if the top hose is firm. If not you have a water pump issue.

 

[John Z]

Where was the steam coming from on the radiator? There are no openings or vented caps. Just a bleed cap that should be sealed. That sounds like a problem to begin with.

 

[aeo]

Fill it up, crank it up, let it warm up and see if the top hose is firm. If not you have a water pump issue.

Thank you. That seems simple enough.

Where was the steam coming from on the radiator? There are no openings or vented caps. Just a bleed cap that should be sealed. That sounds like a problem to begin with.

I couldn’t really tell and I didn’t see any coolant on the radiator. My thought is that there was pressure causing it to leak some coolant from the hose clamps. It was weird how it just stopped. There was some coolant on the grill and on the ground under each side of the radiator.

If it is the thermostat is the best plan to just boil that in a pot of water and see if it opens?

 

[MountainD]

If it is the thermostat is the best plan to just boil that in a pot of water and see if it opens?

that certainly works. To increase accuracy, I always monitor H2O temp and when it opens though. Should open pre-boil…

 

[aeo]

Added probably half a gallon of coolant at the radiator, still probably wants more, ran it with the expansion tank cap off on an decent incline. Got it up to temp- top coolant hose was easy to squeeze. IR said it was 120-140 on the hose. Leaking coolant from somewhere and running down the lower coolant hose. Seems like p-gasket or water pump issues to me. Thoughts? This could be one of my least favorite things to deal with. How can I tell if I need to order a new water pump because I don't want to take this apart twice.

 

[javelinadave]

Sorry you keep having luck like this. If that is what you suspect replace the p gasket and renew the water pump. Easier than cooking the head and dealing with that scenario.

 

[Shearpin]

Only thing worse than coolant system faults is anything that contains hydraulic fluid.

A leaky p-gasket should be easy to spot - the seam between the housing and block is visible. My experience with water pumps is that if it isn’t the main gasket - another source of fluid may be through the drive pulley shaft. Look for fluid running down the back of the pulley.

Were all your hose mating surfaces clean? I had a top hose leak that wouldn‘t go away. Took it off and found a small bit of crusty, dried coolant on the bottom of the hose mounting surface that was causing a slow but persistent leak.

Regarding your overheating - I had a similar 300tdi cooling system experience a few years ago. I replaced a worn out radiator and things got worse instead of better. My experience has been this diesel requires a lot of bleeding to get any air bubbles out. Open the header tank, thermostat housing port and let it run while sensually massaging all the hoses - don’t forget the heater matrix hoses at the back.

Hope this helps… I fought with my issues for a couple weeks and still pull out the IR heat gun in a hot spell…

Henry

 

[aeo]

Sorry you keep having luck like this. If that is what you suspect replace the p gasket and renew the water pump. Easier than cooking the head and dealing with that scenario.

Part of me worries that I have already cooked the head. I just assume it’s the water pump or gaskets based on where the coolant is on the ground and it’s running along the lower coolant hose.

Any reason to go genuine on this vs Proline?

 

[JimC]

I usually fill as much as I can from a raised heater hose to make sure there is fluid in there.

i think there is a Britrest Mike video about a water pump that was DOA, maybe check that out.

 

[aeo]

Looks like it has a pinhole leak. It's an allisport radiator. Thoughts on repair vs replacement?

 

[John Z]

That's an aluminum unit, should be able to be repaired. Personally if you're not overly attached to it, I'd look to get rid of it when you come across a good deal. I feel like I see a lot about these having issues like this

 

[javelinadave]

I’m glad nobody suggested adding an egg to your coolant or pouring in some ground black pepper. Both are bad advice.
Definitely get it fixed right or replace it with a new radiator.

 

[aeo]

That's an aluminum unit, should be able to be repaired. Personally if you're not overly attached to it, I'd look to get rid of it when you come across a good deal. I feel like I see a lot about these having issues like this

My next question is about the difference between the RN heavy duty and the allisport aluminum. If I am going to order a replacement is there any reason to go back to aluminum? I'm a quarter of the way to replacement costs for the RN part if I repair it.

 

[John Z]

I went with the RN HD unit. Looking back, I should have picked up the ic upgrade and rad support combo while at it.

When I went from the standard to HD radiator I noticed it looked oem just that it had more rows going across. Prob 2 or more? I'm sure @Z.G knows more though.. I looked at it like any job worth doing is worth doing right..

 

[Range Rover Blues]

I had a lot of trouble getting a TDi to bleed properly and in the end it was that cruddy little cone shaped thing where the radiator and thermostat breathers join, it was full of sludge and stop leak. Swapped it for a new one and it worked much better.