I for some reason seem to be loosing coolant. I dont have any leaking onto the ground and the temp gauge says that its running hot sometimes and sometimes its at normal temp. I also have a check engine light coming on sometimes, but then it goes right back off. I am going on thursday to do a pressure test. if i find out that i have a head gasket leak or something how hard and how long would it take to change out and get fixed. also have any of yall had a problem like this and what was the cause?

 

If you are losing coolant and don't see any on the ground or on the engine or any other obvious leaks, then it's most likely that you have bad head gasket(s), a cracked block, cracked head(s), or a warped head(s). The warped head issue usually arises from previous overheating conditions. How long have you had the truck, and how long has it been doing this? Changing a head gasket can be difficult in these, especially if you have a V8. Mostly the one on the driver's side because you'll have to pull the intake. Changing a head gasket in and of itself is an easy job; it's all the stuff around it that makes it hard. But it's not impossible. Head gaskets are usually changed in pairs, so be sure to get both heads magnafluxed to check for cracks, and checked for warpage and milled flat before reinstalling if necessary. Also, when reinstalling I recommend a new head gasket bolt kit, as the old bolts can stretch; and be VERY sure that you are installing the bolts in the proper sequence and that you are torquing them with a torque wrench. Some head gaskets need to be torqued more than once, so be sure to read your manual. Also, clean out the threaded holes where the head gasket bolts were on the block with an engine cleaning wire brush (they're round and you can get a whole set with all different sizes for $12.99 here 20 Piece Engine Brush Kit). Then blow the holes out with compressed air to remove the debris. You want to see those threads nice and clean with nothing in them. Finally, be sure to put a little anti-seize compound on the new bolt's threads. The main causes of head gasket replacement failure are dry threads not being able to be torqued properly; re-using old, stretched bolts; or warped heads not being checked and milled.

BTW - you didn't say what year Bronco you have. If it's a carbureted model then the job is quite a bit easier. Also, if you do the head gaskets, when you have the heads off this is a good time to install new valve cover gaskets; because that job is a pain in and of itself due to the intake needing to be removed. But if you do the heads then you can easily do the valve covers since you had to remove the intake anyway. Also, if you were thinking of doing a valve job, this would be the time for that too.

 

Ok thanks I will keep all that in mind when I check it. Sorry I forgot to include the engine and year. Its a 1990 351 V8. I've had it for a couple weeks now and not sure of how long its been doing it. The water temp sensor wasn't working till just a couple days ago when I replaced it and been noticing that it sometime goes to the hot side untill I add more coolant then its normal. But I'm just hoping that its nothing major or costly.

 

If it's losing coolant that you can't see, and it runs hot until you put more coolant in, then you almost certainly have one of the problems listed above.

 

So if I do have one of the problems listed above would I have coolant going into the oil? I have checked the oil and it looks normal. Where else could it be going?

 

That's a myth. You won't always see water in the oil if you have one of those issues. Sometimes the coolant is burned away with the fuel, and it sounds like that is happening with your truck. Check the tailpipe after the truck warms up fully and see if there is any water coming out (this must be done with the engine at operating temperature, if it's only a little bit that comes out when first started cold then it's just condensation). So look for water coming from the tailpipe when the engine is fully warmed up. Also look for a very fine, white smoke. If it's burning coolant it will make some smoke but it's very hard to see it, it's a very fine, almost invisible white smoke.

 

Ok thanks ill look tomorrow and let you know tomorrow night

 

Check all the hoses and parts of the cooling system for stains, engine issues would be the last thing to check. Sometimes the leaks are so small the water evaporates before reaching the ground.

 

Yes, he said he was doing a pressure test on Thursday. That should locate any external leaks. But I don't think a leak that tiny would require him to keep having to fill up the radiator all the time. That's why I suggested the other issues. I certainly hope for his sake that it is such a leak, but if I was a betting man I'd go with a cracked block. That's what I've most often found when dealing with this issue. And he said he just got the Bronco two weeks ago and he's already had to fill and refill his coolant. My gut feeling is that someone unloaded a probem on him. If so, mater73, don't feel bad, it's happened to all of us. I got burned by this exact same issue myself. If there's coolant in the radiator it's undetectable with a normal inspection, but as soon as you burn off enough coolant it becomes a probem. My guess is that it's probably overheated in the past, which made the problem worse by warping the heads or something.

On the other hand there's still a chance of a very small leak, but I've never come across a leak so small that you can't see it but large enough to require constant filling of coolant. But I do hope for your sake that it is happening here. It would be nice to see a mountain reduced to a molehill once in a while! But PLEASE DO NOT start tearing the engine apart just yet. Wait until you do your pressure test and use a flashlight to visually inspect every single place where coolant goes. Some can't even been seen unless you know where to look, such as the smal one under the distributor. I never knew it was there until mine blew out one day. Also be sure that your heater core is not leaking. The pressure test should uncover any leaks in these areas. Be sure that you have your vent's temp control set to "hot" when you do the pressure test so that the coolant flows through all of the heater hoses and heater core.

PS - also notice how he said he had to fix the temperature gauge. It's possible that an unscrupulous seller disconnected it or something because of the running hot issue.

 

so i see the normal condensation in the tail pipes but im not seeing any white smoke coming from the pipes at operating temps either not even a little bit and its chilly today so i thought that i would see something but didnt. im going to go ahead and get the pressure test done today and ill post the results tonight after im done. i just hope its nothing to bad and its just a molehill and not a mountian. i have to drive from kentucky to texas with in the next few weeks so i hope its an easy fix. i checked all the hoses and i cant see any leaks coming from anywhere even with the small ones but im going to keep checking. im also starting to wonder if my gauge or new temp sensor might just be jacked up because this morning it went to the far right (hot) back to normal temps within like ten minutes then later it just stayed between normal and hot. if it is a cracked block am i going to have to replace the whole thing or can that be fixed ? but as far as the seller goes as far as i can tell he didnt mess with the temp guage everything was connected, but on the same not i am finding out stuff that he didnt tell me or that he beat around when asked.

but thank JBronco for all the help and encourgement and ill keep updating on what i discover. also you can search post by me in this forum and see the other issues ive had.

 

OK so we did the pressure test but didnt have any luck because the pressure tester at the shop wasnt working right. but after talking with the people up there and describing my problem that ive been having and doing some futher checking we determined that its the head gaskets. so this weekend im going to get all the parts and then on monday start tearing into it.

 

JBronco does it again! (unfortunately in this case; sorry to be the bearer of bad news). OK now - Be sure to have the heads Magnafluxed as well as checked for warpage, which can usually be milled away if it's not too bad. Also put in new valve covers as soon as the heads are on and there's nothing in the way. Because that job in and of itself is difficult, because you have to remove a bunch of stuff in the way but you'll be moving that stuff to get to the heads anyway. So now is the time. Also, as I said, buy a set of NEW head bolts, clean the inside of the threads on the block very clean (you can use a plumber's wire fitting brush, available at any hardware store - you don't need a whole engine cleaning brush kit). Make sure those threads are nice and clean and shiny, and free of debris, then blow them out with compressed air. Also be sure to put a little anti-seize compound on the threads of the new bolts; and be SURE to follow the manual's order of tightening the bolts and what torque they need to be. With some vehicles you have to torque them 2 or 3 times. So go by the the instructions and follow whatever it says. I have a Ford official shop manual for a 1990 Bronco because that's what year mine is; if you want I can scan the pages that deal with head gasket replacement and post them here.

Remember, the number one reasons for failed head gasket repair, imo, are using the old bolts, not using anti-seize compound on the bolt threads, and not cleaning the threads in the block. Because they can bind and you won't be able to torque them correctly if you don't follow those steps.

Finally, one word of warning - that test you did pointed to head gaskets, but it can also mean cracked block or warped/cracked heads. The test looks for the presence of coolant where it should not be, but it doesn't really differentiate between head gaskets and cracked/warped block or heads. You can have the heads magnafluxed to check for cracks but unless you feel like rebuilding the motor and pulling the whole block then just cross your fingers and hope the block is ok! Somebody dumped their problem on you, but chalk it up as a learning experience. We've all been there. Good luck!

 

ok so heres my new question of the day, but first a little background. so im on my way to work this morning around 5:30 and the outside temp is about 40deg. on the way to work the water temp guage is hanging out around the hot side but it did go have a visit with the normal temps range a few time but mostly hung out on the hot side. once i got to work i parked in the parking lot and let it idel for about 10 minutes and the temp guage hung out with the normal temps and not the hot temps. about an hour later after the truck being off i went back to it and noticed for the first time coolant on the ground, and the overflow tank empty, but the radiator was for the most part full. i added a little coolant to it and by a little i mean very little before the radiator was full. since then the engine has not ran hot one single time and the temps have been on the low side. so heres the question.... even though the pressure tester wasnt working like it was suppose to is it possible that it was pushing enought air in to maybe clear a clog that could of been causing poor flow thus causing hot temps? because like i said there has been no over heating at all today since this morning on the way to work and i normally have to fill it at least 3 times a day just to help it stay cool. so i am hoping that this is a good thing, because i really dont want to do anything with the head gaskets and spend a crap load of money on parts and other things that could go wrong if i dont have too. atleast not 2 weeks before i take a trip.

 

Anything is possible. Since you saw coolant on the ground, and the overflow tank was empty, it could be one of two things - that you have a tiny leak somewhere, or that the engine, after being shut off, boiled over and spit coolant on the ground. That's not unheard of. When you turn your engine off, it actually gets hotter for a period of time because there's no coolant circulating, and a vehicle with a bad head gasket/cracked head/ cracked block will spit some coolant then. I really hope for your sake that it's just a leak - I certainly don't want you to have engine trouble! I'm more than happy to be wrong in cases like this! I would check every single place where coolant may leak with a fine toothed comb. In my case, my Bronco was plagued with coolant leaks a few years ago, around 100K, and I just got sick of it and replaced everything that flows coolant, and I mean everything. Every single hose and clamp, even the partly metal one that runs across the top of the radiator (if you get one be sure to get the right one, you need to know if you have heavy duty cooling or not); the coolant recovery tank, the heater core, the radiator, the thermostat and the water pump. That was several years ago and I haven't had a single coolant leak since. But be sure you get all of the hoses if you do this, and use new clamps. There is one small hose that's easy to miss, it's runs under the distributor. That blew out on me one day because nobody ever changed it - they probably didn't even know it was there. Don't forget to check your freeze plugs - I had to replace one of mine. I also had a coolant leak at the front of the intake manifold gasket, but if you have a leak there you'd almost certainly see it because coolant would puddle on the engine underneath. Even replace the hose that runs from the coolant recovery tank to the radiator, and use a hose clamp at each end, even though they don't have them from the factory, at least mine were just pushed on. The reason that I replaced my coolant recovery tank was because it was leaking at the top, I could see coolant coming out of it at the seam. And check the coolant recovery tank fill cap; our Broncos tend to blow coolant from that cap so I used aluminum foil to cover the fill hole and then snapped the cap over that. My truck hasn't leaked anything for years now (knock on wood!) and I can park on any driveway at app 160K.

I wish you good luck with your Bronco, I hope it turns out to be something easy!

 

Thanks I hope its something easy too.