Engine/Transmission (1994 - 1998) low coolant level and related issues

[Bug1]

<b>The story so far:</b>

Truck is a 96 that I purchased from another TDR member in January, on the 2000 mile drive home we were a little bit low on coolant, but the PO had removed an Espar previous to sale so I attributed the low coolant to needing to bleed the system after it was opened up. Now we have put 5K miles on the truck and in this time I have had to top up the coolant level twice. Last night we drove home from a 400 mile trip and when I got home the coolant was about a gallon and a half low! It was topped up when we left so this is a significant loss. Despite this leak the system never get hot, it will barely get to the 190 degree mark on the gauge, and I can always pull the radiator cap off when the engine is hot with barely a hiss of steam.



There is a flourescent tracer in the coolant and using a big blacklight on a dark night there is no obvious leakage anywhere. The weep hole on the water pump is dry. There is no foaming of the oil or other signs of water contamination. The only thing I can figure is the coolant is leaking into the combustion chamber at the head gasket. I am going to get a Stant pressure tester and check the pressure integrity of the system and look for leaks one more time just to be sure...



Other relevant info: the truck is very mild, #11 plate and a gov spring kit. Never over EGT, never overheated, driven firmly but intelligently. Previous owner overheated once due to an external head gasket leak, the head was replaced with a new one for good measure and the correct new gasket was installed with the proper torqueing procedure. I wont mention neames but he is a member in good standing here and I trust his judgement.



<b>Questions for the experts here:</b>



How likely is it that the coolant would leak into the combustion chamber but the engine would continue to run fine and not completely blow out the gasket?



Keeping in mind that the truck has never gotten over 190 degrees in the entire time I have had it, do you think any damage was done due to the low coolant? i. e. localized overheating where air pockets have formed?



Is there anything else I should be checking before I assume this is an internal head gasket leak? Keeping in mind that there are no drips, no wet spots or anything to indicate an external leak...



Thanks in advance for your help!



-Zach

 

[CATCRACKER]

this is not going to help much but you have a leak somewhere and that sucks at least you did not buy a truck from a tdr memeber with a cracked timing gear cover like i did. of course you may have a cracked block.



look at you coolant while it is running if you see lots of air bubbles then you probabaly have a cracked head, block etc.

 

[Bandit1]

i jsut had my headgasket replaced, i drove around for a year with low coolant, no damage done but i was pushing my luck. i was leaking between all cylinders and had chunks missing from the gasket. but no mechanic could tell me a def answer, until it finaly blew. if i would have broek a compressison ring between the cylinders and the ignition process was allowed to bridge the cylinder walls a notch could have been worn causing major costly repairs. also if it blows while you are driving you could hydrolock the pistons and that will cause costly repairs also, i always heard bubbling when i shut down and had coolant blowing out the overflow bottle. get it pressure tested and ge the coolant tested for exhuast gases, but those arent always true mine was done both multiple times and still no answer. if you have any questions feel free to ask. truck is now fire ringed by ADT and is running better than ever. dont presss your luck with this prob.

 

[DSiemens]

With no pressure on the rad cap, you definitely have a leak. If the coolant was going into a cylinder, the exhaust should be kinda white/smoky.

Mine leaked near the thermostat housing. When the motor was warm, you would never see any coolant on the ground as the heat evaporated it. Are there any coolant streaks down the side of the block?

 

[Bug1]

I borrowed a pressure tester and that made short work of finding the problem. The #$#% head gasket is leaking out the very back right next to the firewall. At 15psi it really starts flowing!



I am still new to the CTD thing, where is the best place to buy parts? Is it a lot cheaper to buy online, or should I just go down to the Cummins place and buy over the counter?



Any recommendations on what else to check/replace while I have the head off? New bolts?



-Zach

 

[tURBOdIEZEl]

had the same issue, leaking coolent. ended up replacing the o-ring around the thremostat... when it was pressure tested i found out my head gasket was leaking "slightly"

the mechanic put some "aluma-seal" in my system and said to just keep an eye on it. argh.

 

[Andy Redmond]

Bug:



Take the engine serial number to the Cummins parts folks. .



Have the head stripped and magnafluxed. They are famous for cracking at the valve seat. Many of the TDR members are far cheaper on good cylinder heads than you'll do at the Cummins place.



Have the head checked for warp. . if its needs to be decked thicker head gaskets are available.



Look for archive posts by Joe Donnelly, he has shared some tips and tricks on how to do a quality repair.







I usually change head bolts, although the plastic service tool will let you ck. the go no go length.



Post again if you get stuck. The Cummins or FSM are helpful and give torq. sequence and tightening instructions.